Substrate processing method

ABSTRACT

A substrate processing method comprising steps for forming a copper film on a surface of a substrate. These steps includes the step of filling a first metal in the trenches so as to form a plated film of the first metal on an entire surface of the substrate by electroplating, wherein the electromagnetic field is adjusted by the virtual anode so that differences of thickness of the plated film between the central portion and the peripheral portion of the substrate being minimized, and polishing and removing the plated film by pressing the substrate to the polishing surface, wherein the pressures pressing the substrate to the polishing surface at a central portion and a peripheral portion are adjusted.

This is a Divisional Application of U.S. patent application Ser. No.10/787,218, filed Feb. 27, 2004 now U.S. Pat. No. 6,828,225 which is acontinuation of U.S. patent application Ser. No. 10/182,835, now U.S.Pat. No. 6,790,763, which is the national phase of PCT/JP01/10590, filedDec. 4, 2001.

TECHNICAL FIELD

This invention relates to a substrate processing method, and moreparticularly, to those used to fill fine recesses formed on the surfaceof a semiconductor substrate with copper, thereby forming a copperinterconnection pattern.

BACKGROUND ART

In recent years, with the increased throughput and the higherintegration of semiconductor chips, moves to use copper (Cu) with lowelectric resistivity and high electromigration resistance as a metallicmaterial for forming an interconnection circuit on a semiconductorsubstrate, instead of aluminum or aluminum alloy, have becomenoticeable. A copper interconnection of this type is generally formed byfilling fine recesses formed on the surface of the substrate withcopper. Methods for forming the copper interconnection include CVD,sputtering, and plating.

FIGS. 62A to 62C show an example to form a copper interconnection bycopper plating in the sequence of steps. As shown in FIG. 62A, aninsulating film 2 of SiO₂ is deposited on a conductive layer 1 a on asemiconductor substrate 1 having formed a semiconductor device. Acontact hole 3 and a trench 4 for an interconnection are formed in theinsulating film 2 by lithography and etching technology. A barrier layer5 of TaN or the like is formed on the contact hole 3 and the trench 4,and a copper seed layer 7 is further formed thereon as a power supplylayer for electroplating.

As shown in FIG. 62B, copper plating is applied to the surface of asemiconductor substrate W to fill copper into the contact hole 3 and thetrench 4 of the semiconductor substrate 1 and also deposit a copper film6 on the insulating film 2. Then, the copper film 6 and the barrierlayer 5 on the insulating film 2 is removed by chemical mechanicalpolishing (CMP), thus making the surface of the copper film 6 filledinto the contact hole 3 and the trench 4 for an interconnection lieflush with the surface of the insulating film 2. In this manner, aninterconnection composed of the plated copper film 6 is formed as shownin FIG. 62C.

FIG. 63 shows the entire constitution of a substrate processingapparatus for performing the above series of interconnection formationsteps in a clean room. In the clean room, an insulating film formingdevice 10, a lithography and etching device 12, a barrier layer formingdevice 14, a copper seed layer forming device 26, a copper platingdevice 18, and a CMP device 20 are housed. The substrate W having theinsulating film 2 formed by the insulating film forming device 10 isaccommodated into a substrate cassette 22, and transported to thelithography and etching device 12 for a subsequent step. The substrate Whaving the contact hole 3 and the trench 4 for an interconnection formedin the lithography and etching device 12 is transported, while beinghoused in the substrate cassette 22, to the barrier layer forming device14 for a subsequent step. The substrate W thus processed in therespective devices is transported, while being accommodated in thesubstrate cassette 22, to subsequent steps, whereby the series ofinterconnection formation steps are sequentially performed.

FIG. 64 schematically shows a conventional general configuration of acopper plating device for use in the above type of copper plating. Thisplating device includes a cylindrical plating tank 602 opening upwardand holding a plating liquid 600 inside, and a rotatable substrateholder 604 adapted to detachably hold a substrate W, such as asubstrate, so as to face downward, and disposing the substrate W at aposition at which it closes the upper end opening portion of the platingtank 602. Inside the plating tank 602, a flat plate-shaped anode plate(anode) 606 immersed in the plating liquid 600 to serve as an anodicelectrode is horizontally placed, and the seed layer of the substrate Wis to serve as cathodic electrode. The anode plate 606 comprises acopper plate or a gathering of copper balls.

A plating liquid supply pipe 610 having a pump 608 mounted inside isconnected to the center of the bottom of the plating tank 602. Outsideof the plating tank 602, a plating liquid receptacle 612 is placed.Further, the plating liquid which has flowed into the plating liquidreceptacle 612 is returned to the pump 608 through a plating liquidreturn pipe 614.

Because of this structure, the substrate W is held facedown at the topof the plating tank 602 by the substrate holder 604, and rotated in thiscondition. With a predetermined voltage being applied between the anodeplate 606 (anodic electrode) and the seed layer of the substrate W(cathodic electrode), the pump 608 is driven to introduce the platingliquid 600 into the plating tank 602, whereby a plating electric currentis flowed between the anode plate 606 and the seed layer of thesubstrate W to form a plated copper film on the lower surface of thesubstrate W. At this time, the plating liquid 600 which has overflowedthe plating tank 602 is recovered by the plating liquid receptacle 612,and circulated.

Copper easily diffuses into a silicon dioxide film during asemiconductor manufacturing process to deteriorate the insulatingproperties of the silicon dioxide film, and causes cross contaminationduring the steps of transportation, storage and processing of thesubstrate. Copper may also contaminate the interior of the clean room.

In detail, the substrate having the copper seed layer formed thereonused to be transported, while being placed in the substrate cassette, tothe copper plating device, and the substrate having the copper filmformed in the copper plating device used to be transported, while beingput in the substrate cassette, to the CMP device. Thus, copper particlesand copper ions adhering to the substrate, which are very active andharmful to other processes, were likely to diffuse into the clean room.

When a plated copper film is deposited on the surface of the substrateby use of a copper electroplating device, a voltage between the centerof the seed layer of the substrate and the anode differs from a voltagebetween the periphery of the seed layer of the substrate and the anode,because of the electrical resistance of the copper seed layer formed onthe surface of the substrate. Thus, the film thickness of the platedcopper film on the periphery of the substrate is greater than the filmthickness of the plated copper film at the center of the substrate.

When the plated copper film thicker on the periphery than at the centerof the substrate is polished by a polishing device, the plated copperfilm remains unpolished on the periphery of the substrate, or the platedcopper film at the center is scraped excessively, which is a phenomenoncalled dishing.

The distance between the anode and the substrate may be fully lengthenedto increase the electric resistance of the plating liquid itself,thereby diminishing the influence of the electric resistance of thecopper seed layer. This measure can make the film thickness of theplated copper film more uniform, but leads to upsizing of the apparatus.

DISCLOSURE OF INVENTION

The present invention has been accomplished in light of the foregoingcircumstances. Its object is to provide a substrate processing methodwhich can deposit the plated copper film on the surface of the substratemore uniformly; which can polish away a surplus plated copper filmwithout leaving unscraped portions or causing dishing; and which canprevent the contamination of the interior of the clean room withhazardous copper coming from the copper film, such as the copper seedlayer or copper film, formed on the surface of the substrate.

According to an aspect of the present invention, there is provided amethod of filling a metal in fine trenches in a surface of a substrate,comprising: forming a barrier layer on the substrate, and a seed layeron the barrier layer; providing an electroplating apparatus having afirst substrate holder for holding the substrate, a plating bathcontaining a plating liquid, an anode, and a virtual anode to adjustelectromagnetic field; providing a polishing apparatus having a secondsubstrate holder for holding the substrate to press the substrateagainst a polishing surface at different pressures at a central portionand a peripheral portion of the substrate; transferring the substratewith the barrier layer and the seed layer to the electroplatingapparatus; holding the substrate in the first substrate holder andplacing the substrate in the plating liquid; generating electromagneticfield; filling a first metal in the trenches and forming a plated filmof the first metal on an entire surface of the substrate byelectroplating, wherein the electromagnetic field is adjusted by thevirtual anode so that differences of thickness of the plated filmbetween the central portion and the peripheral portion of the substratebeing minimized; removing the substrate from the plating bath; washingand drying the substrate in the electroplating apparatus; transferringthe substrate to the polishing apparatus; holding the substrate in thesecond substrate holder; polishing and removing the plated film bypressing the substrate to the polishing surface, wherein the pressurespressing the substrate to the polishing surface at a central portion anda peripheral portion are adjusted; washing and drying the substrate inthe polishing apparatus; and transferring the substrate from thepolishing apparatus.

According to another aspect of the present invention there is provided amethod of filling a metal in trenches in a surface of a substrate,comprising; providing an electroplating apparatus; providing a polishingapparatus having a substrate holder for holding the substrate to pressthe substrate against a polishing surface at different pressures at acentral portion and a peripheral portion of the substrate; forming abarrier layer on the substrate; transferring the substrate with thebarrier layer to the electroplating apparatus; holding the substrate ina first plating liquid in the electroplating apparatus; electroplating afirst layer on the entire surface of the barrier layer using the firstplating liquid; holding the substrate in a second plating liquid in theelectroplating apparatus; filling a metal in the trenches covered by thefirst layer and forming a second plating layer of the metal on thesurface of the substrate using the second plating liquid; washing anddrying the substrate in the electroplating apparatus; transferring thesubstrate to the polishing apparatus; holding the substrate in thesubstrate holder; polishing the second plating layer by pressing thesubstrate to the polishing surface, wherein the pressures pressing thesubstrate to the polishing surface at a central portion and a peripheralportion are adjusted; washing and drying the substrate in the polishingapparatus; and transferring the substrate from the polishing apparatus.

According to still another aspect of the present invention there isprovided a method of filling a metal in trenches in a surface of asubstrate, comprising: forming a barrier layer on the substrate, and aseed layer on the barrier layer; providing an electroplating apparatushaving a first substrate holder for holding the substrate, a platingbath containing a plating liquid, and an anode; providing a polishingapparatus having a second substrate holder for holding the substrate topress the substrate against a polishing surface; transferring thesubstrate with the barrier layer and the seed layer to theelectroplating apparatus; reinforcing the seed layer by depositing anadditional metal in electroplating unit or electroless-plating unit;holding the substrate in the first substrate holder and placing thesubstrate in the plating liquid; generating electromagnetic field;filling a first metal in the trenches and forming a plated film of thefirst metal on an entire surface of the substrate by electroplating;removing the substrate from the plating bath; washing and drying thesubstrate in the electroplating apparatus; transferring the substrate tothe polishing apparatus; holding the substrate in the second substrateholder; polishing and removing the plated film by pressing the substrateto the polishing surface; cap-plating a second metal to form aprotective plated layer on the plated film of the polished substrateafter polishing; and washing and drying the substrate.

According to still another aspect of the present invention there isprovided a method of filling a metal in trenches in a surface of asubstrate, comprising; providing a plating apparatus; providing apolishing apparatus having a substrate holder for holding the substrateto press the substrate against a polishing surface at differentpressures at a central portion and a peripheral portion of thesubstrate; forming a barrier layer on the substrate; transferring thesubstrate with the barrier layer to the plating apparatus; holding thesubstrate in a first plating liquid in the plating apparatus;electroless-plating a first layer on the entire surface of the barrierlayer using the first plating liquid in the electroplating apparatus;holding the substrate in a second plating liquid in the platingapparatus; generating electromagnetic field between the substrate and ananode; filling a metal in the trenches covered by the first layer andforming a second plating layer of the metal on the surface of thesubstrate using the second plating liquid; washing and drying thesubstrate in the plating apparatus; transferring the substrate to thepolishing apparatus; holding the substrate in the substrate holder;polishing the second plating layer by pressing the substrate to thepolishing surface, wherein the pressures pressing the substrate to thepolishing surface at a central portion and a peripheral portion areadjusted; washing and drying the substrate in the polishing apparatus;and transferring the substrate from the polishing apparatus.

The above and other objects, features, and advantages of the presentinvention will be apparent from the following description when taken inconjunction with the accompanying drawings which illustrates preferredembodiments of the present invention by way of example.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view showing the entire constitution of a substrateprocessing apparatus according to an embodiment of the presentinvention;

FIG. 2 is an entire layout drawing of a plating device;

FIG. 3 is a view showing a loading/unloading portion of the platingdevice;

FIG. 4 is a schematic sectional view of a plating unit of the platingdevice;

FIG. 5 is a schematic view of a substrate cleaning device of the platingdevice;

FIG. 6 is a schematic sectional view showing another example of thesubstrate cleaning device of the plating device;

FIG. 7 is an entire layout drawing of a CMP device;

FIG. 8 is a view showing the relationship between a top ring and apolishing table of the CMP device;

FIG. 9 is a cross-sectional view showing a relationship between a topring and a polishing table of the CMP device;

FIG. 10 is a vertical cross-sectional view showing the top ring shown inFIG. 9;

FIG. 11 is a bottom view of the top ring shown in FIG. 9;

FIGS. 12A through 12E are vertical cross-sectional views showing otherexamples of contact members (central bag and ring tube) in a top ring ofthe CMP device;

FIG. 13 is a vertical cross-sectional view showing another example ofcontact members (central bag and ring tube) in a top ring of the CMPdevice;

FIGS. 14A and 14B are vertical cross-sectional views showing otherexamples of contact members (central bag and ring tube) in a top ring ofthe CMP device;

FIG. 15 is a vertical cross-sectional view showing another top ring ofthe CMP device;

FIG. 16 is a vertical cross-sectional view showing still another exampleof contact members (central bag and ring tube) in a top ring of the CMPdevice;

FIG. 17 is a plan view showing a substrate transport box;

FIG. 18 is a front view showing the substrate transport box;

FIG. 19 is a sectional plan view showing a different example of thesubstrate transport box;

FIG. 20 is a sectional view taken on line A—A of FIG. 19;

FIG. 21 is a front view of the different substrate transport box;

FIG. 22 is a bottom view of the different substrate transport box;

FIG. 23 is a view attached to a description of the state of use of thedifferent substrate transport box;

FIG. 24 is a sectional plan view showing a further different example ofthe substrate transport box;

FIG. 25 is a sectional view taken on line B—B of FIG. 24;

FIG. 26 is a view showing another example of the entire constitution ofthe substrate processing apparatus;

FIG. 27 is a view showing still another example of the entireconstitution of the substrate processing apparatus;

FIG. 28 is a schematic sectional view showing an example of a copperplating device having a film thickness distribution adjusting function;

FIG. 29 is a schematic sectional view showing another example of thecopper plating device having the film thickness distribution adjustingfunction;

FIG. 30 is a schematic sectional view showing another example of thecopper plating device having the film thickness distribution adjustingfunction;

FIG. 31 is a schematic sectional view showing another example of thecopper plating device having the film thickness distribution adjustingfunction;

FIG. 32 is a schematic sectional view showing another example of thecopper plating device having the film thickness distribution adjustingfunction;

FIG. 33 is a schematic sectional view showing another example of thecopper plating device having the film thickness distribution adjustingfunction;

FIG. 34 is a schematic sectional view showing another example of thecopper plating device having the film thickness distribution adjustingfunction;

FIG. 35 is a schematic sectional view showing another example of thecopper plating device having the film thickness distribution adjustingfunction;

FIG. 36 is a schematic sectional view showing another example of thecopper plating device having the film thickness distribution adjustingfunction;

FIG. 37 is a schematic sectional view showing another example of thecopper plating device having the film thickness distribution adjustingfunction;

FIG. 38 is a schematic sectional view showing another example of thecopper plating device having the film thickness distribution adjustingfunction;

FIG. 39 is a schematic sectional view showing another example of thecopper plating device having the film thickness distribution adjustingfunction;

FIG. 40 is a schematic sectional view showing another example of thecopper plating device having the film thickness distribution adjustingfunction;

FIG. 41 is a perspective view showing an example of a CMP device havinga polishing amount adjusting function;

FIG. 42 is a longitudinally sectional front view of FIG. 41;

FIGS. 43A and 43B are views showing a modification of FIG. 42, FIG. 43Abeing a plan view, and FIG. 43B being a longitudinally sectional frontview;

FIG. 44 is a perspective view showing another example of the CMP devicehaving the polishing amount adjusting function;

FIG. 45 is a longitudinally sectional front view of FIG. 44;

FIG. 46 is a plan view of FIG. 45;

FIG. 47 is a layout plan view showing another example of the substrateprocessing apparatus;

FIG. 48 is a layout plan view showing still another example of thesubstrate processing apparatus;

FIGS. 49A through 49E are views attached to a description of two-stageplating;

FIG. 50 is a view attached to a description of a modification of FIGS.49A through 49E;

FIG. 51 is a block diagram showing an example of measuring the electricresistance of a copper seed layer to control the copper plating deviceand the CMP device;

FIG. 52 is a sectional view showing an example of an electric terminalmember serving concurrently as a copper seed layer resistance measuringterminal and a cathode;

FIG. 53 is a perspective view showing a part of FIG. 52;

FIGS. 54A through 54C are sectional views showing different examples ofthe electric terminal;

FIGS. 55A and 55B are sectional views attached to a description of acentering mechanism with different electric terminal members;

FIG. 56 is a view attached to a description of measurement of theelectric resistance of the copper seed layer with the use of theelectric terminal member shown in FIG. 52;

FIG. 57 is a view attached to a description of another method formeasuring the electric resistance of the copper seed layer;

FIGS. 58A and 58B are views attached to a description of still anothermethod for measuring the electric resistance of the copper seed layer;

FIGS. 59A through 59C are views attached to a description of a furthermethod for measuring the electric resistance of the copper seed layer;

FIG. 60 is a sectional view showing another example of the electricterminal member serving concurrently as a copper seed layer resistancemeasuring terminal and a cathode;

FIG. 61 is a view attached to a description of measurement of theelectric resistance of the copper seed layer with the use of theelectric terminal member shown in FIG. 60;

FIGS. 62A through 62C are views showing an example of forming a copperinterconnection by copper plating in the sequence of steps;

FIG. 63 is a view showing the entire constitution of a conventionalsubstrate processing apparatus;

FIG. 64 is a schematic sectional view showing a conventional platingdevice;

FIG. 65 is a plan view of an example of a substrate plating apparatus;

FIG. 66 is a schematic view showing airflow in the substrate platingapparatus shown in FIG. 65;

FIG. 67 is a cross-sectional view showing airflows among areas in thesubstrate plating apparatus shown in FIG. 65;

FIG. 68 is a perspective view of the substrate plating apparatus shownin FIG. 65, which is placed in a clean room;

FIG. 69 is a plan view of another example of a substrate platingapparatus;

FIG. 70 is a plan view of still another example of a substrate platingapparatus;

FIG. 71 is a plan view of still another example of a substrate platingapparatus;

FIG. 72 is a view showing a plan constitution example of thesemiconductor substrate processing apparatus;

FIG. 73 is a view showing another plan constitution example of thesemiconductor substrate processing apparatus;

FIG. 74 is a view showing still another plan constitution example of thesemiconductor substrate processing apparatus;

FIG. 75 is a view showing still another plan constitution example of thesemiconductor substrate processing apparatus;

FIG. 76 is a view showing still another plan constitution example of thesemiconductor substrate processing apparatus;

FIG. 77 is a view showing still another plan constitution example of thesemiconductor substrate processing apparatus;

FIG. 78 is a view showing a flow of the respective steps in thesemiconductor substrate processing apparatus illustrated in FIG. 77;

FIG. 79 is a view showing a schematic constitution example of a beveland backside cleaning unit;

FIG. 80 is a view showing a schematic constitution of an example of anelectroless-plating apparatus;

FIG. 81 is a view showing a schematic constitution of another example ofan electroless-plating apparatus;

FIG. 82 is a vertical sectional view of an example of an annealing unit;

FIG. 83 is a transverse sectional view of the annealing unit;

FIG. 84 is a plan view showing another plating unit;

FIG. 85 is a sectional view taken on line A—A of FIG. 84;

FIG. 86 is an enlarged sectional view of a substrate holder and acathode portion;

FIG. 87 is a front view of a substrate holder;

FIG. 88 is a sectional view of a cathode portion;

FIG. 89 is a plan view of an electrode arm;

FIG. 90 is a longitudinal sectional front view of FIG. 89;

FIG. 91 is a sectional view taken on line E—E of FIG. 89;

FIG. 92 is an enlarged view showing a part of FIG. 91 in an enlargedmanner;

FIG. 93 is a plan view of a state in which a housing of an electroportion of the electrode arm has been removed;

FIG. 94 is a flow diagram showing the flow of reinforcing process stepsof a seed layer; and

FIGS. 95A through 95C illustrate, in a sequence of process steps, forforming interconnects made of copper by plating a surface of asubstrate, thereafter forming a protective layer on the interconnectsselectively.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will now be described indetail with reference to the accompanying drawings, which in no waylimit the invention.

FIG. 1 shows the entire constitution of a substrate processing apparatusaccording to an embodiment of the present invention. In a clean room, aninsulating film forming device 10, a lithography and etching device 12,a barrier layer forming device 14, a copper seed layer forming device16, a copper plating device 18, and a CMP device 20 are housed. On thesurface of a substrate W, an insulating film 2 is formed by theinsulating film forming device 10, a contact hole 3 and a trench 4 foran interconnection are formed by the lithography and etching device 12,a barrier layer 5 is formed by the barrier layer forming device 14, anda copper seed layer 7 is formed by the copper seed layer forming device16, in this sequence, as shown in FIG. 62A. Copper plating is applied tothe surface of the substrate W by the copper plating device 18 to form acopper film 6, as shown in FIG. 62B. Then, chemical mechanical polishingis carried out on the surface of the substrate W by the CMP device 20 toform an interconnection composed of the copper film 6 shown in FIG. 62C.

The copper seed layer forming device 16 for forming the copper seedlayer 7 on the surface of the substrate W, the copper plating device 18for forming the copper film 6 by applying copper plating to the surfaceof the substrate W, and the CMP device 20 for treating the substrate Wexposed the copper film 6 are separated by partition walls in the cleanroom, and are also isolated from the clean room. The substrates W withthe copper seed layer 7 or the copper film 6 exposed on the surfacethereof are housed in a substrate cassette 22. The substrate cassette 22is placed in a substrate transport box 24, and the substrates W aretransported, in a hermetically sealed condition, to a next step by thesubstrate transport box 24 together with the substrate cassette 22. Thatis, transport of the substrates W from the copper seed layer formingdevice 16 to the copper plating device 18, transport of the substrates Wfrom the copper plating device 18 to the CMP device 20, and transport ofthe substrates W from the CMP device 20 are performed, with thesubstrates W being housed in the substrate cassette 22, and with thesubstrate cassette 22 being sealed up in the substrate transport box 24.Namely, these transport activities are performed, with the substrates Wbeing isolated from the clean room.

FIG. 2 shows the entire configuration of the copper plating device 18.This plating device 18 is housed in a rectangular facility 26 separatedby partition walls, and is adapted to perform copper plating of asemiconductor substrate continuously. This facility 26 is partitioned bya partition wall 28 into a plating space 30 and a clean space 32, andthe plating space 30 and the clean space 32 are each capable of airintake and exhaust independently. The partition wall 28 is provided withan openable/closable shutter (not shown). The pressure of the cleanspace 32 is lower than the atmospheric pressure, and higher than thepressure of the plating space 30. Thus, air inside the clean space 32does not flow out into the clean room outside the facility 26, and airinside the plating space 30 does not flow into the clean space 32.

A loading/unloading portion 35 for placing the substrate transport box24 housing the substrate cassettes 22, and two cleaning/drying devices27 for cleaning (rinsing) a plated substrate with pure water and dryingthe cleaned substrate are disposed inside the clean space 32. A fixedand rotatable first transport device (four-axis robot) 29 fortransporting the substrate is further provided. The cleaning/dryingdevice 27 used is, for example, of the type which has cleaning liquidsupply nozzles for supplying ultrapure water to both of the face sideand the back side of the substrate, and spins the substrate at a highspeed to dewater and dry it.

Inside the plating space 30, there are disposed two pretreatment units33 for pretreating the substrate before plating, and turning thesubstrate upside down by an inverting machine 31; four plating units 34for applying copper plating to the surface of the substrate facedown;and two first substrate stages 36 a and 36 b for placing and holding thesubstrate. A self-propelled, rotatable second transport device(four-axis robot) 38 for transporting the substrate is also provided.

In the clean space 32, there are disposed two substrate cleaning devices40 for cleaning the plated substrate with a chemical solution, such asan acid solution or an oxidizing agent solution; and two secondsubstrate stages 42 a and 42 b located between the substrate cleaningdevices 40 and the cleaning/drying devices 27. A fixed, rotatable thirdtransport device (four-axis robot) 44 for transporting the substrate isprovided at a position interposed between the two substrate cleaningdevices 40.

One of the first substrate stages 36 b, and one of the second substratestages 42 b, are adapted to allow the substrate to be washed with water,and are each provided with an inverting machine 31 for turning thesubstrate upside down.

The first transport device 29 is adapted to transport the substrateamong the substrate cassette 22 placed and housed in theloading/unloading portion 35, the cleaning/drying devices 27, and thesecond substrate stages 42 a, 42 b. The second transport device 38 isadapted to transport the substrate among the first substrate stages 36a, 36 b, the pretreatment units 33, and the plating units 34. The thirdtransport device 44 is adapted to transport the substrate among thefirst substrate stages 36 a, 36 b, the substrate cleaning devices 40,and the second substrate stages 42 a, 42 b.

Inside the facility 26, a container 46 for accommodating anadjusting-operation substrate is incorporated below the first substratestage 36 a. The second transport device 38 is adapted to withdraw theadjusting-operation substrate from the container 46, and return thissubstrate to the container 46 after an adjusting operation ends. In thismanner, the container 46 for accommodating the adjusting-operationsubstrate is disposed inside the facility 26, thus making it possible toprevent contamination or a decrease in throughput associated with theintroduction of the adjusting-operation substrate from the outside foran adjusting operation.

The position of disposition of the container 46 may be any position inthe facility 26 as long as it is a position allowing theadjusting-operation substrate to be withdrawn and accommodated by any ofthe transport devices. By disposing the container 46 near the firstsubstrate stage 36 a, an adjusting operation using theadjusting-operation substrate can be started for pretreatment, followedby plating, and the substrate after cleaning/drying can be returned intothe container 46.

The pretreatment units for applying pretreatment for increasingwettability of the substrate with a plating can be omitted.Alternatively, a preplating unit for performing preplating for thepurpose of reinforcing the copper seed layer formed on the substratebefore execution of plating can be installed in place of one of theplating units or one of the pretreatment units. In this case, awater-washing unit for performing water washing between preplating andplating and/or after plating is installed instead of the pretreatmentunit.

The transport device 29 used is one having two drop-in hands, one ofwhich located upper side is a dry hand, the other located lower sidebeing a wet hand. The transport devices 38, 44 used are each one havingtwo drop-in hands, both of which are wet hands. Needless to say,however, such transport devices are not restrictive.

Next, the flow of the substrate in the plating device 18 will beoutlined. The substrate is housed in the substrate cassette 22 with itssurface (semiconductor device formation side, or processing side)directed upward, and the substrate cassette 22 is housed in thesubstrate transport box 24. In this state, the substrates aretransported to and placed in the loading/unloading portion 35. The firsttransport device 29 withdraws the substrate from the substrate cassette22, moves it toward the second substrate stage 42 a, and places it onthe second substrate stage 42 a. The third transport device 44 transfersthe substrate present on the second substrate stage 42 a to the firstsubstrate stage 36 a. Then, the second transport device 38 receives thesubstrate from the first substrate stage 36 a, and passes it on to thepretreatment unit 33. After completion of pretreatment by thepretreatment unit 33, the inverting machine 31 turns the substrateupside down so that the surface of the substrate faces downward. Theinverted substrate is handed to the second transport device 38 again.The second transport device 38 passes the substrate on to a plating headof the plating unit 34.

After the substrate is plated and dehydrated of the plating liquid inthe plating unit 34, the substrate is passed on to the second transportdevice 38, which carries the substrate to the first substrate stage 36b. The substrate is inverted by the inverting machine 31 of the firstsubstrate stage 36 b so that its face side faces upward. In the invertedstate, the substrate is moved to the substrate cleaning device 40 by thethird transport device 44. The substrate, which has been cleaned withthe chemical solution, rinsed with pure water, and spin-extracted in thesubstrate cleaning device 40, is carried to the first substrate stage 42b by the third transport device 44. Then, the first transport device 29receives the substrate from the first substrate stage 42 b, andtransfers the substrate to the cleaning/drying device 27, which rinsesthe substrate with pure water and spin-dries it. The spin-driedsubstrate is transported by the first transport device 29, and returnedto the substrate cassette 22 within the substrate transport box 24transported to the loading/unloading portion 35.

Here, pretreatment by the pretreatment unit can be omitted. When thepreplating unit is installed, the substrate withdrawn from the substratecassette is subjected to preplating by the preplating unit, and after awater-washing step or without a water-washing step, the substrate isplated by the plating unit. After plating, the substrate is put to, ornot put to, a water-washing step, and transported to the first cleaningdevice.

FIG. 3 is a view showing the loading/unloading portion 35. Theloading/unloading portion 35 is provided with stages 50 placing thesubstrate transport boxes 24 housing substrate cassettes 22. When thesubstrate transport box 24 is placed on an elevating stand 52 of thestage 50, the elevating stand 52 and a bottom plate 24 a of thesubstrate transport box 24 are locked together. The bottom plate 24 a ismounted on the bottom of the substrate transport box 24 so as to closean opening of the bottom of substrate transport box 24. However,simultaneously with the locking of the elevating stand 52 and the bottomplate 24 a, the stage 50 and the substrate transport box 24 intimatelycontact each other, and the bottom plate 24 a is liberated from thesubstrate transport box 24 for a free state.

The elevating stand 52 is coupled to an elevating mechanism 54, and thebottom plate 24 a placing the substrate cassette 22, once released fromthe substrate transport box 24 to become free, is moved up and downintegrally with the elevating stand 52. When the elevating stand 52 andthe bottom plate 24 a are confirmed to have been locked, the elevatingstand 52 descends, and the bottom plate 24 a placing the substratecassette 22 moves downward, thereby making it possible to withdraw thesubstrate W from the substrate cassette 22.

FIG. 4 shows the plating unit 34, which mainly comprises a substantiallycylindrical plating tank 62 holding a plating liquid 60, and a platinghead 64 disposed above the plating tank 62 and adapted to hold thesubstrate W. FIG. 4 shows a state of the plating unit 34 being at aplating position at which the substrate W is held by the plating head 64and the liquid level of the plating liquid 60 is raised.

The plating tank 62 has a plating chamber 68 open upward and having ananode 66 disposed at the bottom, and a plating vessel 70 containing theplating liquid 70 in the plating chamber 68. On the innercircumferential wall of the plating vessel 70, plating liquid ejectionnozzles 72 horizontally protruding toward the center of the platingchamber 68 are arranged at equal intervals along the circumferentialdirection. These plating liquid ejection nozzles 72 communicate with aplating liquid supply passage extending vertically within the platingvessel 70.

A punch plate 74 provided with many holes, for example, of about 3 mm isdisposed at a position above the anode 66 in the plating chamber 68 soas to thereby prevent a black film, which is formed on the surface ofthe anode 66, from being brought up by the plating liquid 60 and flowedout.

The plating vessel 70 is also provided with a first plating liquiddischarge port 76 for pulling out the plating liquid 60 in the platingchamber 68 from the peripheral edge of the bottom of the plating chamber68, a second plating liquid discharge port 80 for discharging theplating liquid 60 which has overflowed a dam member 78 provided in anupper end portion of the plating vessel 70, and a third plating liquiddischarge port 82 for discharging the plating liquid before overflowingthe dam member 78. The plating liquids flowing through the secondplating liquid discharge port 80 and the third plating liquid dischargeport 82 are mixed at a lower end portion of the plating vessel 70 anddischarged.

Because of this structure, when the amount of a plating supplied islarge during plating, the plating liquid is discharged to the outsidethrough the third plating liquid discharge port 82, and simultaneouslycaused to overflow the dam member 78 and discharged to the outsidethrough the second plating liquid discharge port 80. When the amount ofa plating supplied is small during plating, the plating liquid isdischarged to the outside through the third plating liquid dischargeport 82, and simultaneously caused to pass through an opening (notshown) provided in the dam member 78, and discharged to the outsidethrough the second plating liquid discharge port 80. These contrivancespermit easy adaptation to the magnitude of the amount of a plating.

Near the periphery of the interior of the plating chamber 68, a verticalstream regulating ring 84 and a horizontal stream regulating ring 86 aredisposed by having the outer peripheral end of the horizontal streamregulating ring 86 secured to the plating vessel 70. These streamregulating rings 84 and 86 serve to push up the center of the platingliquid surface by an upper flow of the plating liquid 60 divided intoupper and lower flows in the plating chamber 68, to smooth the lowerflow, and make the distribution of an electric current density moreuniform.

The plating head 64 has a rotatable, bottomed, cylindrical housing 90open downward and having an opening 88 in a circumferential wallthereof, and vertically movable press rods 94 having a press ring 92attached to the lower ends thereof.

The housing 90 is connected to an output shaft 98 of a motor 96, and isadapted to rotate by driving of the motor 96. The press rods 94 aresuspended at predetermined positions along the circumferential directionof a ring-shaped support frame 108 rotatably supported via a bearing 106at the lower end of a slider 104 movable upward and downward by theactuation of a guide-equipped cylinder 102 secured to a support 100surrounding the motor 96. Thus, the press rods 94 move up and downaccording to the actuation of the cylinder 102, and when the substrate Wis held, are adapted to rotate integrally with the housing 90.

The support 100 is mounted on a slide base 114 screwed to, and movingupward and downward integrally with, a ball screw 112 rotating inaccordance with the driving of a motor 110. Further, the support 100 issurrounded with an upper housing 116, and moved up and down togetherwith the upper housing 116 in accordance with the driving of the motor110. A lower housing 118 surrounding the periphery of the housing 90during plating is attached to the upper surface of the plating vessel70.

FIGS. 84 to 93 shows another example of a plating unit 2012. The platingunit 2012, as shown in FIG. 84, is provided with a substrate treatmentsection 2020 for performing plating treatment and treatment incidentalthereto. A plating liquid tray 2022 for containing the plating liquid isdisposed adjacent to the substrate treatment section 2020. There is alsoprovided an electrode arm portion 2030 having an electrode portion 2028which is held at the free end of an arm 2026 swingable about a rotatingshaft 2024 and which is swung between the substrate treatment section2020, and a plating liquid tray 2022. Furthermore, apre-coating/recovering arm 2032, and fixed nozzles 2034 for ejectingpure water or a chemical liquid such as ion water, and further a gas orthe like toward a substrate are disposed laterally of the substratetreatment section 2020. In this embodiment, three of the fixed nozzles2034 are disposed, and one of them is used for supplying pure water.

The substrate treatment section 2020, as shown in FIGS. 85 and 86, has asubstrate holder 2036 for holding a substrate W with its surface, to beplated, facing upward, and a cathode portion 2038 located above thesubstrate holder 2036 so as to surround a peripheral portion of thesubstrate holder 2036. Further, a substantially cylindrical bottomed cup2040 surrounding the periphery of the substrate holder 2036 forpreventing scatter of various chemical liquids used during treatment isprovided so as to be vertically movable by an air cylinder 2042.

The substrate holder 2036 is adapted to be raised and lowered by aircylinders 2044 between a lower substrate transfer position A, an upperplating position B, and a pretreatment/cleaning position C intermediatebetween these positions. The substrate holder 2036 is also adapted torotate at an arbitrary acceleration and an arbitrary velocity integrallywith the cathode portion 2038 by a rotating motor 2046 and a belt 2048.A substrate carry-in and carry-out opening (not shown) is provided inconfrontation with the substrate transfer position A in a side surfaceof the plating unit 2012. When the substrate holder 2036 is raised tothe plating position B, a seal member 2090 and cathode electrodes 2088(to be described below) of the cathode portion 2038 are brought intocontact with the peripheral edge portion of the substrate W held by thesubstrate holder 2036. On the other hand, the cup 2040 has an upper endlocated below the substrate carry-in and carry-out opening, and when thecup 2040 ascends, the upper end of the cup 2040 reaches a position abovethe cathode portion 2038 closing the substrate carry-in and carry-outopening, as shown by imaginary lines in FIG. 86.

The plating liquid tray 2022 serves to wet a plating liquid impregnatedmaterial 2110 and an anode 2098 (to be described later on) of theelectrode arm portion 2030 with a plating liquid, when plating has notbeen performed.

As shown in FIG. 87, the substrate holder 2036 has a disk-shapedsubstrate stage 2068 and six vertical support arms 2070 disposed atspaced intervals on the outer circumferential edge of the substratestage 2068 for holding a substrate W in a horizontal plane on respectiveupper surfaces of the support arms 2070. Chucking fingers 2076 arerotatably mounted on upper ends of the support arms 2070 for pressingthe substrate W downwardly and gripping the outer circumferential edgeof the substrate W.

The chucking fingers 2076 have respective lower ends coupled to upperends of pressing pins 2080 that are normally urged to move downwardly bycoil springs 2078. When the pressing pins 2080 are moved downwardly, thechucking fingers 2076 are rotated radially inwardly into a closedposition. A support plate 2082 is disposed below the substrate stage2068 for engaging lower ends of the opening pins 2080 and pushing themupwardly.

When the substrate holder 2036 is located in the substrate transferposition A shown in FIG. 85, the pressing pins 2080 are engaged andpushed upwardly by the support plate 2082, so that the chucking fingers2076 rotate outwardly and open. When the substrate stage 2068 iselevated, the opening pins 2080 are lowered under the resiliency of thecoil springs 2078, so that the chucking fingers 2076 rotate inwardly andclose.

As shown in FIG. 88, the cathode portion 2038 comprises an annular frame2086 fixed to upper ends of vertical support columns 2084 mounted on theperipheral edge of the support plate 2082 (see FIG. 87), a plurality ofcathode electrodes 2088 attached to a lower surface of the annular frame2086 and projecting inwardly, and an annular sealing member 2090 mountedon an upper surface of the annular frame 2086 in covering relation toupper surfaces of the cathode electrodes 2088. The sealing member 2090is adapted to have an inner circumferential edge portion inclinedinwardly downwardly and progressively thin-walled, and to have an innercircumferential end suspending downwardly.

When the substrate holder 2036 has ascended to the plating position B,as shown FIG. 86, the cathode electrodes 2088 are pressed against theperipheral edge portion of the substrate W held by the substrate holder2036 for thereby allowing electric current to pass through the substrateW. At the same time, an inner circumferential end portion of the sealmember 2090 is brought into contact with an upper surface of theperipheral edge of the substrate W under pressure to seal its contactportion in a watertight manner. As a result, the plating liquid suppliedonto the upper surface (surface to be plated) of the substrate W isprevented from seeping from the end portion of the substrate W, and theplating liquid is prevented from contaminating the cathode electrodes2088.

As shown in FIGS. 89 through 93, the electrode head 2028 of theelectrode arm portion 2030 comprises a housing 2094 coupled to a freeend of the swing arm 2026 through a ball bearing 2092, a cylindricalsupport frame 2096 surrounding the housing 2094, and an anode 2098 fixedby having a peripheral edge portion gripped between the housing 2094 andthe support frame 2096. The anode 2098 covers an opening of the housing2094, which has a suction chamber 2100 defined therein. In the suctionchamber 2100, there is disposed a diametrically extending plating liquidintroduction pipe 2104 connected to a plating liquid supply pipe 2102which extends from the plating liquid supply unit (not shown), and heldin abutment against an upper surface of the anode 2098. A plating liquiddischarge pipe 2106 communicating with the suction chamber 2100 isconnected to the housing 2094.

The plating liquid introduction pipe 2104 is effective to supply theplating liquid uniformly to the surface, to be plated, if the platingliquid introduction pipe 2104 is of a manifold structure. Specifically,the plating liquid introduction pipe 2104 has a plating liquidintroduction passage 104 a extending continuously in its longitudinaldirection, and a plurality of plating liquid introduction ports 2104 bspaced at a given pitch along the plating liquid introduction passage2104 a and extending downwardly therefrom in communication therewith.The anode 2098 has a plurality of plating liquid supply ports 2098 adefined therein at positions corresponding to the plating liquidintroduction ports 2104 b. The anode 2098 also has a number ofvertically extending through holes 2098 b defined therein over itsentire region. The plating liquid that is introduced from the platingliquid supply pipe 2102 into the plating liquid introduction pipe 2104flows through the plating liquid introduction ports 2104 b and theplating liquid supply ports 2098 a to a position below the anode 2098.With the anode 2098 being immersed in the plating liquid, the platingliquid discharge pipe 2106 is evacuated to discharge the plating liquidbelow the anode 2098 via the through holes 2098 b and the suctionchamber 2100 from the plating liquid discharge pipe 2106.

In this embodiment, a plating liquid impregnated material 2110comprising a water-retaining material and covering the entire surface ofthe anode 2098 is attached to the lower surface of the anode 2098. Theplating liquid impregnated material 2110 is impregnated with the platingliquid to wet the surface of the anode 2098, thereby preventing a blackfilm from falling onto the plated surface of the substrate by drying,and oxidizing, and simultaneously facilitating escape of air to theoutside when the plating liquid is poured between the surface, to beplated, of the substrate and the anode 2098.

The plating liquid impregnated material 2110 has both functions ofretaining liquid and passing liquid therethrough, and has excellentchemical resistance. Specially, the plating liquid impregnated material2110 has endurance against an acid plating liquid including sulfuricacid having high concentration. The plating liquid impregnated material2110 comprises, for example, a woven fabric of polypropylene to preventelution of the impurity in the sulfuric acid solution from having a badinfluence to the plating efficiency (plating speed, resistivity andfilling characteristics). The plating liquid impregnated material 2110may comprises at least one material of polyethylene, polyester,polyvinyl chloride, Teflon, polyvinyl alcohol, polyurethane, andderivatives of these materials, other than polypropylene. Nonwovenfabric or sponge-like structure may use in place of woven fabric. Porousceramics and sintered polypropylene made of Alumina and SiC and the likeare available.

Many fixing pins 2112 each having a head portion at the lower end arearranged such that the head portion is provided in the plating liquidimpregnated material 2110 so as not to be releasable upward and a shaftportion pierces the interior of the anode 2098, and the fixing pins 2112are urged upward by U-shaped plate springs 2114, whereby the platingliquid impregnated material 2110 is brought in close contact with thelower surface of the anode 2098 by the resilient force of the platesprings 2114 and is attached to the anode 2098. With this arrangement,even when the thickness of the anode 2098 gradually decreases with theprogress of plating, the plating liquid impregnated material 2110 can bereliably brought in close contact with the lower surface of the anode2098. Thus, it can be prevented that air enters between the lowersurface of the anode 2098 and the plating liquid impregnated material2110 to cause poor plating.

When the impregnated material 2110 has a sufficient strength such as aporous ceramics, the anode may be placed on the impregnated materialwithout using pins for fixing the impregnated material.

When the substrate holder 2036 is in the plating position B (see FIG.86), the electrode head 2028 is lowered until the gap between thesubstrate W held by the substrate holder 2036 and the plating liquidimpregnated material 2110 becomes about 0.5 to 3 mm, for example. Then,the plating liquid is supplied from the plating liquid supply pipe 2102to fill the gap between the upper surface, to be plated, of thesubstrate W and the anode 2098 while impregnating the plating liquidimpregnated material 2110 with the plating liquid, thus plating theupper surface of the substrate W.

FIG. 5 is a schematic view of the substrate cleaning device 40. As shownin FIG. 5, the substrate W, such as a substrate, having a circuit formedin areas excluding a peripheral edge portion of its surface is grippedby spin chucks 120 at a plurality of locations along the circumferentialdirection of the peripheral edge portion, and horizontally held by asubstrate holder 122. Thus, the substrate W is adapted to rotatehorizontally at a high speed. The substrate may be held vertically by aholding mechanism, but its horizontal holding will be described herein.A center nozzle 124 is disposed downwardly above a nearly central partof the surface of the substrate W held by the substrate holder 122, andan edge nozzle 126 is disposed downwardly above the peripheral edgeportion of the surface of the substrate. Furthermore, two back nozzles128 and 130 are disposed upwardly beneath a nearly central part of theback side of the substrate W. The peripheral edge portion of thesubstrate refers to an area at the peripheral edge of the substratewhere no circuit has been formed, or an area at the peripheral edge ofthe substrate where a circuit has been formed and which is finally notused as a chip. The center nozzle 124 can be installed at a desiredposition between the center and the peripheral edge portion of thesurface of the substrate, but a feed solution from the nozzle issupplied to the center of the substrate. The center of the substraterefers to, preferably, within 20% of the diameter of the substrate, morepreferably within 10% of the diameter of the substrate. Similarly, theback nozzles 128, 130 can be installed at desired positions between thecenter and the peripheral edge portion of the back side of thesubstrate, but the feed solution from the nozzles is preferably suppliedto the center of the substrate.

As shown in FIG. 6, there may be one back nozzle 128 provided, and theedge nozzle 126 may be movable vertically or movable horizontally alongthe diametrical direction of the substrate W so that a height H from thesubstrate W or a range of movement width L, in the horizontal directionis adjustable. Moreover, the periphery of the substrate holder 122 maybe surrounded with a waterproof cover 132. Besides, a fixed nozzle (notshown) may be installed on an intra-device side surface of thewaterproof cover 132 or the like, and pure water, deionized water orother chemical solution (an acid solution, an alkali solution, a surfaceactive agent, or a corrosion inhibitor) may be supplied to the substrateaccording to the purpose.

Next, a cleaning method by this cleaning device will be described.

First, the substrate W is horizontally rotated integrally with thesubstrate holder 122, with the substrate W being horizontally held bythe substrate holder 122 via the spin chucks 120. In this condition, anacid solution is supplied from the center nozzle 124 to the center ofthe surface of the substrate W. Even though a natural oxide film ofcopper has been formed at a circuit formation portion on the surface ofthe substrate W, this natural oxide film is immediately removed by theacid solution spreading over the entire surface of the substrate W asthe substrate W rotates. Thus, the natural oxide film does not grow. Forthe acid solution, there may be used, for example, any one of, or acombination of, hydrochloric acid, hydrofluoric acid, sulfuric acid,citric acid, and oxalic acid which are generally used in a cleaning stepof a semiconductor device manufacturing process. However, the acidsolution may be a solution of any non-oxidizing acid. Hydrofluoric acidcan be used for cleaning of the back side of the substrate W (to bedescribed later on), and thus is preferred for sharing of the samechemical for different purposes. Also, hydrofluoric acid is preferablyin a concentration of 0.1% by weight or more, in consideration of itseffect of removing the oxide film. To avoid roughening of the coppersurface, its concentration is preferably 5% by weight or less.

On the other hand, an oxidizing agent solution is supplied continuouslyor intermittently from the edge nozzle 126 to the peripheral edgeportion of the substrate W. By this treatment, the copper film, etc.formed on the upper surface and end surface of the peripheral edgeportion of the substrate W are rapidly oxidized with the oxidizing agentsolution, and etched with the acid solution, which has beensimultaneously supplied from the center nozzle 124 and has spread overthe entire surface of the substrate W. As a result, the copper film,etc. are dissolved and removed. Etching with the acid solution-occursalso at sites other than the location of supply of the oxidizing agentsolution, so that the concentration and the amount of supply of the acidsolution need not be increased. For the oxidizing agent solution, theremay be used, for example, any one of, or a combination of, ozone,hydrogen peroxide, nitric acid, and hypochlorite which are generallyused in a cleaning step of a semiconductor device manufacturing process.If an ozone water is used, its amount is preferably 20 ppm or more, but200 ppm or less. In the case of hydrogen peroxide, its preferredconcentration is 10% by weight or more, but 80% by weight or less. Ifhypochlorite is used, its preferred concentration is 1% by weight ormore, but 50% by weight or less.

At the same time, an oxidizing agent solution and an acid solution, suchas hydrofluoric acid, are supplied simultaneously or alternately fromthe back nozzles 128 and 130 to the center of the back side of thesubstrate W. By this treatment, copper, etc. adhering to the back sideof the substrate W can be oxidized with the oxidizing agent solution,along with the silicon of the substrate, and etched away with the acidsolution.

In supplying the oxidizing agent solution and the acid solution from thetwo back nozzles 128 and 130 separately, simultaneously or alternately,if the supply of the oxidizing agent solution is stopped first, ahydrophobic surface is obtained; if the supply of the acid solution isstopped first, a hydrophilic surface is obtained. In either case, theback side of the substrate can be adjusted to one suitable forfulfilling the requirements of the subsequent process.

For the oxidizing agent solution, there can be cited, for example, anyone of, or a combination of, ozone, hydrogen peroxide, nitric acid, andhypochlorite, as stated earlier. For the acid solution, there may beused the aforementioned non-oxidizing acid, such as hydrochloric acid,hydrofluoric acid, sulfuric acid, citric acid, or oxalic acid. Inaddition, copper can be removed with the use of an oxidizing acid, suchas nitric acid, because there is no circuit on the back side of thesubstrate W unlike its face side. If an acid solution of an oxidizingacid such as nitric acid is used, this acid solution itself plays therole of an oxidizing agent solution, so that the oxidizing acid solutioncan be used alone, without using an oxidizing agent solution.Preferably, the oxidizing agent solution should be the same as theoxidizing agent solution supplied to the peripheral edge portion of thesurface of the substrate W in order to decrease the types of thechemicals used.

FIG. 7 shows a whole structure of CMP device 20. As shown in FIG. 7, theCMP device 20 comprises a loading/unloading portion 140 for placingsubstrate transport boxes 24 which house the substrate cassette 24. Theloading/unloading portion 140 includes four stages 50 shown in FIG. 3. Atransfer robot 144 having two hands is provided on rails 142 so that thetransfer robot 144 can move along the rails 142 and access therespective substrate cassettes 22 on the respective loading/unloadingstages 50.

The transfer robot 144 has two hands which are located in a verticallyspaced relationship, and the lower hand is used only for taking out asubstrate from the substrate cassette 22 and the upper hand is used onlyfor returning the substrate to the substrate cassette 22. Thisarrangement allows that a clean substrate which has been cleaned isplaced at an upper side and is not contaminated. The lower hand is avacuum attraction-type hand for holding a substrate under vacuum, andthe upper hand is a recess support-type hand for supporting a peripheraledge of a substrate by a recess formed on the hand. The vacuumattraction-type hand can hold a substrate and transport the substrateeven if the substrate is not located at a normal position in thesubstrate cassette 22 due to a slight displacement, and the recesssupport-type hand can transport a substrate while keeping the substrateclean because dust is not collected unlike the vacuum attraction-typehand. Two cleaning apparatuses 146 and 148 are disposed at the oppositeside of the substrate cassettes 22 with respect to the rails 142 of thetransfer robot 144. The cleaning apparatuses 146 and 148 are disposed atpositions that can be accessed by the hands of the transfer robot 144.Between the two cleaning apparatuses 146 and 148 and at a position thatcan be accessed by the transfer robot 144, there is provided a waferstation 158 having four wafer supports 150, 152, 154 and 156. Thecleaning apparatuses 146 and 148 have a spin-dry mechanism for drying asubstrate by spinning the substrate at a high speed, and hence thetwo-stage cleaning or three-stage cleaning of the substrate can beconducted without replacing any cleaning module.

An area B in which the cleaning apparatuses 146 and 148 and the waferstation 158 having the wafer supports 150, 152, 154 and 156 are disposedand an area A in which the substrate cassettes 22 and the transfer robot144 are disposed are partitioned by a partition wall 160 so that thecleanliness of the area B and the area A can be separated. The partitionwall 160 has an opening for allowing substrates to pass therethrough,and a shutter 162 is provided at the opening of the partition wall 160.A transfer robot 164 having two hands is disposed at a position wherethe transfer robot 164 can access the cleaning apparatus 146 and thethree wafer supports 150, 154 and 156, and a transfer robot 166 havingtwo hands is disposed at a position where the transfer robot 166 canaccess the cleaning apparatus 148 and the three wafer supports 152, 154and 156.

The wafer support 150 is used to transfer a substrate between thetransfer robot 144 and the transfer robot 164 and has a sensor 168 fordetecting whether there is a substrate or not. The wafer support 152 isused to transfer a substrate between the transfer robot 144 and thetransfer robot 166 and has a sensor 170 for detecting whether there is asubstrate or not. The wafer support 154 is used to transfer a substratefrom the transfer robot 166 to the transfer robot 164, and has a sensor172 for detecting whether there is a substrate or not and rinsingnozzles 178 for supplying a rinsing liquid to prevent a substrate fromdrying or to conduct rinsing of a substrate. The wafer support 156 isused to transfer a substrate from the transfer robot 164 to the transferrobot 166, and has a sensor 176 for detecting whether there is asubstrate or not and rinsing nozzles 178 for supplying a rinsing liquidto prevent a substrate from drying or to conduct rinsing of a substrate.The wafer supports 154 and 156 are disposed in a commonwater-scatter-prevention cover which has an opening defined therein fortransferring substrates therethrough, the opening being combined with ashutter 188. The wafer support 154 is disposed above the wafer support156, and the wafer support 154 serves to support a substrate which hasbeen cleaned and the wafer support 156 serves to support a substrate tobe cleaned, so that the cleaned substrate is prevented from beingcontaminated by rinsing water which would otherwise fall thereon. Thesensors 168, 170, 172 and 174, the rinsing nozzles 174 and 178, and theshutter 180 are schematically shown in FIG. 7, and their positions andshapes are not illustrated exactly.

The transfer robot 164 and the transfer robot 166 have the respectivetwo hands which are located in a vertically spaced relationship. Therespective upper hands of the transfer robot 164 and the transfer robot166 are used for transporting a substrate which has been cleaned to thecleaning apparatuses or the wafer supports of the wafer station 158, andthe respective lower hands of the transfer robot 164 and the transferrobot 166 are used for transporting a substrate which has not cleaned ora substrate to be polished. Since the lower hand is used to transfer asubstrate to or from a reversing device, the upper hand is notcontaminated by drops of a rinsing water which fall from an upper wallof the reversing device.

A cleaning apparatus 182 is disposed at a position adjacent to thecleaning apparatus 146 and accessible by the hands of the transfer robot164, and another cleaning apparatus 184 is disposed at a positionadjacent to the cleaning apparatus 148 and accessible by the hands ofthe transfer robot 166.

All the cleaning apparatuses 146, 148, 182 and 184, the wafer supports150, 152, 154 and 156 of the wafer station 158, and the transfer robots164 and 166 are placed in the area B. The pressure in the area B isadjusted so as to be lower than the pressure in the area A. Each of thecleaning apparatuses 182 and 184 is capable of cleaning both surfaces ofa substrate.

The CMP device 20 has a housing 190 composed of partition walls forenclosing various components therein. The housing 190 constitutes anenclosing structure. The interior of the housing 190 is partitioned intoa plurality of compartments or chambers (including the areas A and B) bypartitions 160, 192, 194, 196 and 198.

A polishing chamber separated from the area B by the partition wall 198is formed, and is further divided into two areas C and D by thepartition wall 198. In each of the two areas C and D, there are providedtwo turntables, and a top ring for holding a substrate and pressing thesubstrate against the turntables during polishing. That is, theturntables 200 and 202 are provided in the area C, and the turntables204 and 206 are provided in the area D. Further, the top ring 208 isprovided in the area C and the top ring 210 is provided in the area D.

An abrasive liquid nozzle 212 for supplying an abrasive liquid to theturntable 200 in the area C and a dresser 214 for dressing the turntable200 are disposed in the area C. An abrasive liquid nozzle 216 forsupplying an abrasive liquid to the turntable 204 in the area D and adresser 218 for dressing the turntable 204 are disposed in the area D. Adresser 220 for dressing the turntable 202 in the area C is disposed inthe area C, and a dresser 222 for dressing the turntable 206 in the areaD is disposed in the area D. The turntables 202 and 206 may be replacedwith wet-type thickness measuring devices for measuring the thickness ofa layer on a substrate. If such wet-type thickness measuring devices areprovided, then they can measure the thickness of a layer on a substrateimmediately after it is polished, and hence it is possible to furtherpolish the polished substrate or control a polishing process forpolishing a next substrate based on the measured value.

FIG. 8 shows the relationship between the top ring 208 and theturntables 200 and 202. The relationship between the top ring 210 andthe turntables 204 and 206 is the same as that of the top ring 208 andthe turntables 200 and 202. As shown in FIG. 8, the top ring 208 issupported from a top ring head 232 by a top ring drive shaft 230 whichis rotatable. The top ring head 232 is supported by a support shaft 235which can be angularly positioned, and the top ring 210 can access theturntables 200 and 202. The dresser 214 is supported from a dresser head236 by a dresser drive shaft 234 which is rotatable. The dresser head236 is supported by an angularly positionable support shaft 238 formoving the dresser 214 between a standby position and a dressingposition over the turntable 204. The dresser 220 is similarly supportedfrom a dresser head 242 by a dresser drive shaft 240 which is rotatable.The dresser head 242 is supported by an angularly positionable supportshaft 244 for moving the dresser 220 between a standby position and adressing position over the turntable 202.

As shown in FIG. 7, in the area C separated from the area B by thepartition wall 196 and at a position that can be accessed by the handsof the transfer robot 164, there is provided a reversing device 250 forreversing a substrate, and at a position that can be accessed by thehands of the transfer robot 166, there is provided a reversing device252 for reversing a substrate. The partition wall 196 between the area Band the areas C, D has two openings each for allowing substrates to passtherethrough, one of which is used for transferring the substrate to orfrom the reversing device 250 and the other of which is used fortransferring the substrate to or from the reversing device 252. Shutters254 and 256 are provided at the respective openings of the partitionwall 196.

The reversing devices 250 and 252 have a chuck mechanism for chucking asubstrate, a reversing mechanism for reversing a substrate, and asubstrate detecting sensor for detecting whether the chuck mechanismchucks a substrate or not, respectively. The transfer robot 164transfers a substrate to the reversing device 250, and the transferrobot 164 transfers a substrate to the reversing device 252.

A rotary transporter 258 is disposed below the reversing devices 250 and252, and the top rings 208 and 210, for transferring substrates betweenthe cleaning chamber (area B) and the polishing chamber (areas C and D).The rotary transporter 258 has four stages for placing a substrate atequal angular intervals, and can hold a plurality of substrates thereonat the same time. The substrate which has been transported to thereversing device 250 or 252 is transferred to the rotary transporter 258by actuating a lifter 260 or 262 disposed below the rotary transporter258 when the center of the stage of the rotary transporter 258 isaligned with the center of the substrate held by the reversing device250 or 252. The substrate placed on the stage of the rotary transporter258 is transported to a position below the top ring 208 or 210 byrotating the rotary transporter 258 by an angle of 90°. At this time,the top ring 208 or 210 is positioned above the rotary transporter 258beforehand by a swing motion thereof. The substrate is transferred fromthe rotary transporter 258 to the top ring 208 or 210 by actuating apusher 264 or 266 disposed below the rotary transporter 258 when thecenter of the top ring 208 or 210 is aligned with the center of thesubstrate placed on the stage of the rotary transporter 258.

The substrate transferred to the top ring 208 or 210 is held undervacuum by a vacuum attraction mechanism of the top ring 208 or 210, andtransported to the turntable 200 or 204. Thereafter, the substrate ispolished by a polishing surface comprising a polishing cloth or agrinding stone (or a fixed abrasive plate) attached on the turntable 200or 204. The second turntables 202 and 206 are disposed at positions thatcan be accessed by the top rings 208 and 210, respectively. With thisarrangement, a primary polishing of the substrate can be conducted bythe first turntable 200 or 204, and then a secondary polishing of thesubstrate can be conducted by the second turntable 202 or 206.Alternatively, the primary polishing of the substrate can be conductedby the second turntable 202 or 206, and then the secondary polishing ofthe substrate can be conducted by the first turntable 200 or 204. Inthis case, since the second turntable 202 or 206 has a smaller-diameterpolishing surface than the first turntable 200 or 204, a grinding stone(or a fixed abrasive plate) which is more expensive than a polishingcloth is attached to the second turntable 202 or 206 to thereby conducta primary polishing of the substrate. On the other hand, the polishingcloth having a shorter life but being cheaper than the grinding stone(or the fixed abrasive plate) is attached to the first turntable 200 or204 to thereby conduct a finish polishing of the substrate. Thisarrangement or utilization may reduce the running cost of the polishingapparatus. If the polishing cloth is attached to the first turntable andthe grinding stone (or fixed abrasive plate) is attached to the secondturntable, then the turntable system may be provided at a lower cost.This is because the grinding stone (or the fixed abrasive plate) is moreexpensive than the polishing cloth, and the price of the grinding stone(or the fixed abrasive plate) is substantially proportional to thediameter of the grinding stone. Further, since the polishing cloth has ashorter life than the grinding stone (or the fixed abrasive plate), ifthe polishing cloth is used under a relatively light load such as afinish polishing, then the life of the polishing cloth is prolonged.Further, if the diameter of the polishing cloth is large, the chance orfrequency of the contact with the substrate is distributed to thusprovide a longer life, a longer maintenance period, and an improvedproductivity of the semiconductor devices.

After a substrate is polished by the first turntable 200 and before thetop ring 208 moves to the second turntable 202, a cleaning liquid issupplied from cleaning liquid nozzles 270 disposed adjacent to theturntable 200 to the substrate held by the top ring 208 at a positionwhere the top rind 208 is spaced from the turntable 200. Because thesubstrate is rinsed before moving to the second turntable 202, thetransfer of contamination between the turntables is prevented to thusavoid cross contamination of the turntables.

Further, two-stage polishing can be performed in such a manner that apolishing cloth sold under the tradename of IC1000/SUBA400 manufacturedby Rodel Nitta corporation is used for the first polishing surface and apolishing cloth sold under the tradename of POLITEX manufactured byRodel Nitta corporation is used for the second polishing surface, andthe substrate is first polished by the first polishing surface, and thenpolished by the second polishing surface. This two-stage polishing maybe carried out by the use of the two large-sized turntables even if thesmall-sized second turntable is not used. In the above, although thetwo-stage polishing has been described as being conducted by twodifferent polishing cloths, it may be conducted by the same polishingcloth or the same grinding stone. After the substrate is polished by thefirst polishing surface and the second polishing surface, the first andsecond polishing surfaces are dressed by the dressers 214, 218, 220 and222, respectively. The dressing process is a process for recovering thepolishing surface of the turntable which has been degraded by polishingof the substrates. This process is also called conditioning orrectification.

The substrate which has been polished is returned to the reversingdevice 250 or 252 in the reverse route to the above. The substratereturned to the reversing device 250 or 252 is rinsed by pure water orchemicals supplied from rinsing nozzles. Further, the substrate holdingsurface of the top ring 208 or 210 from which the substrate has beenremoved is also cleaned by pure water or chemicals supplied fromcleaning nozzles, and in some cases, the substrate holding surface ofthe top ring 208 or 210 is rinsed for preventing the substrate holdingsurface from being dried. A cleaning nozzle or nozzles for cleaning thepusher are provided on the partition wall. In order to improve yield ofthe semiconductor device or cleaning effect of the substrate, thesubstrate may be rinsed by chemicals in such a state that the substrateis held by the top ring 208 or 210. Further, the substrate may be rinsedby chemicals in such a state that the substrate is held by the rotarytransporter 258. Further, the lifter 260 or 262 may be cleaned bynozzles (described later).

On the right side of FIG. 8, the relationship of the rotary transporter258, the reversing device 250 or 252, the lifter 260 or 262, and thepusher 264 or 266 is shown. As shown in FIG. 8, the reversing unit 250or 252 is disposed above the rotary transporter 258, and the lifters 260or 262 and the pushers 264 or 266 are disposed below the rotarytransporter 258.

Next, transport routes for transporting substrates will be described.

All software is constructed such that all units or devices are freelycombined and set in normal processing routes of the substrates in thepolishing apparatus. Examples of the processing routes are thefollowing:

1) Method (2 cassette parallel processing) in which substrates in onesubstrate cassette 22 are processed in one of the two areas C and D, andsubstrates in another substrate cassette 22 are processed in the otherof the two areas C and D;

2) Method (1 cassette parallel processing) in which substrates in onesubstrate cassette 22 are distributed into the area C and the area Darbitrarily; and

3) Method (serial processing) in which substrates in one substratecassette 22 are processed in one of the areas C and D, and thenprocessed in the other of the areas C and D.

In the cleaning chamber, polished substrates discharged from thepolishing chambers are processed according to any one of the followingsix processes:

A) Process in which substrates are cleaned in two-stages by two arraysof cleaning apparatuses and discharged, i.e., from the cleaningapparatus 182 to the cleaning apparatus 146 and from the cleaningapparatus 184 to the cleaning apparatus 148;

B) Process in which substrates are cleaned in three-stages by one arrayof cleaning apparatuses and discharged, i.e., from the cleaningapparatus 184 to the cleaning apparatus 148 and then to the cleaningapparatus 146 or in three-stages by one array of cleaning apparatusesand discharged, i.e., from the cleaning apparatus 182 to the cleaningapparatus 184 or 148 and then to the cleaning apparatus 146;

C) Process in which substrates are cleaned in three-stages anddischarged, i.e., in one-stage by two cleaning apparatuses, i.e., eitherone of the cleaning apparatuses 182, 184 where no cleaning is beingconducted, and in two-stages by one array of cleaning apparatuses, i.e.,from the cleaning apparatus 148 to the cleaning apparatus 146;

D) Process in which substrates are cleaned in four-stages by one arrayof cleaning apparatuses and discharged, i.e., from the cleaningapparatus 184 to the cleaning apparatus 148 and then to the cleaningapparatus 182 and then to the cleaning apparatus 146;

E) Process in which substrates are cleaned in four-stages by one arrayof cleaning apparatuses and discharged, i.e., from the cleaningapparatus 182 to the cleaning apparatus 184 and then to the cleaningapparatus 148 and then to the cleaning apparatus 146; and

F) Process in which substrates are cleaned in three-stages by one arrayof cleaning apparatuses and discharged, i.e., from the cleaningapparatus 184 to the cleaning apparatus 148 and then to the cleaningapparatus 146, after the substrates which have been polished in a firststage are cleaned by the cleaning apparatus 182 and then polished againin a second stage.

Combinations of the methods 1)–3) and the processes A)–F) provide theirrespective features as follows:

(1-A):

This combination is effective in a case where different processes arecarried out for two substrate cassettes and a case where a plurality oflots of substrates are discharged at a high throughput. If differentprocesses are carried out for the two substrate cassettes, then anapparatus configuration or arrangement provided by a combination of twodry-in and dry-out type polishing apparatuses, for example, is employed.Since this combination offers the greatest throughput, it is used toachieve a higher production capability with the same process beingcarried out on substrates from the two substrate cassettes.

(2-A):

This combination is effective to process substrates in one substratecassette in a short period of time. This combination also allowssubstrates in one substrate cassette to be processed in two arbitrarydifferent types of processes.

(3-A):

In the case where the time required to clean a substrate in at least oneof the two cleaning stages is longer than the time required to polish asubstrate in either one of the two polishing stages, if the two cleaningstages are carried out by one array of cleaning apparatuses, then thepolishing capability is lowered because of the long cleaning time. Inthis case, if the two cleaning stages are carried out by two arrays ofcleaning apparatuses, then polished substrates can be delivered withoutbeing affected by the cleaning time. This combination is highlyeffective in this case.

(1-B):

This combination is used in a case where three or more types of cleaningprocess are required after the polishing process. Since the cleaningprocess is carried out by one array of cleaning apparatuses, theprocessing capability of the cleaning process according to thiscombination is reduced, and the combination is highly effective in acase where the polishing time is longer than the cleaning time.

(2-B):

This combination is used in a case where only one lot is processed, butnot a plurality of lots are processed at once as with the combination(1-B), and offers the same advantages as with the combination (1-B).

(3-B):

This combination is used in a case where three cleaning stages areneeded as with the combination (1-B).

(1-C):

This combination offers the same advantages as with the combination(1-B). If the cleaning time in the first cleaning stage is longer thanthe processing time in another wafer processing unit, then the firstcleaning stage is carried out by two cleaning apparatuses for preventingsubstrates from being jammed at the first cleaning apparatus, therebyincreasing the processing capability.

(2-C):

As with the combination (1-C), this combination is used for the samereason as the combination (2-B).

(3-C):

As with the combination (1-C), this combination is used for the samereason as the combination (3-B).

(1, 2, 3-D, E):

This combination is used in a case where four cleaning stages arerequired in addition to the use of the respective polishing chambers.

(3-F):

In the two-stage polishing process, this combination is used totransport substrates through a cleaning process before the secondpolishing stage for preventing the substrates to which the abrasiveliquid used in the first polishing stage is attached from being polishedin the second polishing stage.

As described above, since the polishing apparatus according to thepresent invention has the two polishing sections having the respectiveturntables 200 and 204, one of the polishing sections can be inspectedand serviced for maintenance while the polishing apparatus is inoperation using the other polishing section.

A cleaning section has the cleaning apparatuses 146, 148, 182 and 184for cleaning substrates. While the polishing apparatus is in operationusing at least one of the cleaning apparatuses, the other cleaningapparatuses can be inspected and serviced for maintenance.

FIG. 9 is a cross-sectional view showing a relationship between a topring and a polishing table of the CMP device. As shown in FIG. 9, apolishing table 304 is disposed underneath a top ring 300, and has apolishing pad 302 attached to an upper surface thereof. A polishingliquid supply nozzle 306 is disposed above the polishing table 304 andsupplies a polishing liquid Q onto the polishing pad 302 on thepolishing table 304.

Various kinds of polishing pads are sold on the market. For example,some of these are SUBA800, IC-1000, and IC-1000/SUBA400 (two-layercloth) manufactured by Rodel Inc., and Surfin xxx-5 and Surfin 000manufactured by Fujimi Inc. SUBA800, Surfin xxx-5, and Surf in 000 arenon-woven fabrics bonded by urethane resin, and IC-1000 is rigid foampolyurethane (single-layer). Foam polyurethane is porous and has a largenumber of fine recesses or holes formed in its surface.

The top ring 300 is connected to a top ring drive shaft 310 by auniversal joint 308. The top ring drive shaft 310 is coupled to a topring air cylinder 314 fixed to a top ring head 312. The top ring aircylinder 314 operates to vertically move the top ring drive shaft 310 tothus lift and lower the top ring 300 as a whole. The top ring aircylinder 314 also operates to press a retainer ring 318 fixed to thelower end of a top ring body 316 against the polishing table 304. Thetop ring air cylinder 314 is connected to a compressed air source (fluidsource) 320 via a regulator R1, which regulates the pressure of airsupplied to the top ring air cylinder 314 for thereby adjusting apressing force with which the retainer ring 318 presses the polishingpad 302.

The top ring drive shaft 310 is connected to a rotary sleeve 322 by akey (not shown). The rotary sleeve 322 has a timing pulley 324 fixedlydisposed therearound. A top ring motor 326 having a drive shaft is fixedto the upper surface of the top ring head 312. The timing pulley 328 isoperatively coupled to a timing pulley 324 mounted on the drive shaft ofthe top ring motor 326 by a timing belt 328. When the top ring motor 326is energized, the timing pulley 330, the timing belt 328, and the timingpulley 324 are rotated to rotate the rotary sleeve 322 and the top ringdrive shaft 310 in unison, thus rotating the top ring 300. The top ringhead 312 is supported on a top ring head shaft 332 fixedly supported ona frame (not shown).

FIG. 10 is a vertical cross-sectional view showing the top ring 300, andFIG. 11 is a bottom view of the top ring 300 shown in FIG. 10. As shownin FIG. 10, the top ring 300 comprises the top ring body 316 in the formof a cylindrical housing with a storage space defined therein, and theretainer ring 318 fixed to the lower end of the top ring body 316. Thetop ring body 316 is made of a material having high strength andrigidity, such as metal or ceramics. The retainer ring 318 is made ofhighly rigid synthetic resin, ceramics, or the like.

The top ring body 316 comprises a cylindrical housing 316 a, an annularpressurizing sheet support 316 b fitted in the cylindrical housing 316a, and an annular seal 316 c fitted over an outer circumferential edgeof an upper surface of the cylindrical housing 316 a. The retainer ring316 is fixed to the lower end of the cylindrical housing 316 a and has alower portion projecting radially inwardly. The retainer ring 318 may beintegrally formed with the top ring body 316.

The top ring drive shaft 310 is disposed above the center of thecylindrical housing 316 a of the top ring body 316. The top ring body316 is coupled to the top ring drive shaft 310 by the universal joint310. The universal joint 310 has a spherical bearing mechanism by whichthe top ring body 316 and the top ring drive shaft 310 are tiltable withrespect to each other, and a rotation transmitting mechanism fortransmitting the rotation of the top ring drive shaft 310 to the topring body 316. The rotation transmitting mechanism and the sphericalbearing mechanism transmit pressing and rotating forces from the topring drive shaft 310 to the top ring body 316 while allowing the topring body 316 and the top ring drive shaft 310 to be tilted with respectto each other.

The spherical bearing mechanism comprises a spherical recess 310 adefined centrally in the lower surface of the top ring drive shaft 310,a spherical recess 316 d defined centrally in the upper surface of thehousing 316 a, and a bearing ball 334 made of a highly hard materialsuch as ceramics and interposed between the spherical recesses 310 a and316 d. The rotation transmitting mechanism comprises a drive pin (notshown) fixed to the top ring drive shaft 310, and a driven pin (notshown) fixed to the housing 316 a. The drive pin is held in drivingengagement with the driven pin while the drive pin and the driven pinare being vertically movable relatively to each other. The rotation ofthe top ring drive shaft 310 is transmitted to the top ring body 316through the drive and driven pins. Even when the top ring body 316 istilted with respect to the top ring drive shaft 310, the drive anddriven pins remain in engagement with each other at a moving point ofcontact, so that the torque of the top ring drive shaft 310 can reliablybe transmitted to the top ring body 316.

The top ring body 316 and the retainer ring 318 secured to the top ringbody 316 jointly have a space defined therein, which accommodatestherein an elastic pad 336 having a lower end surface brought intocontact with the upper surface of the substrate W held by the top ring300, an annular holder ring 340, and a disk-shaped chucking plate(support member) 342 for supporting the elastic pad 336. The elastic pad336 has a radially outer edge clamped between the holder ring 340 andthe chucking plate 342 secured to the lower end of the holder ring 340and extends radially inwardly so as to cover the lower surface of thechucking plate 342, thus forming a space between the elastic pad 336 andthe chucking plate 342.

The chucking plate 342 may be made of metal. However, when the thicknessof a thin film formed on a surface of a substrate is measured by amethod using eddy current in such a state that the substrate to bepolished is held by the top ring, the chucking plate 342 shouldpreferably be made of a non-magnetic material, e.g., an insulatingmaterial such as fluororesin or ceramics.

A pressurizing sheet 344, which comprises an elastic membrane, extendsbetween the holder ring 340 and the top ring body 316. The pressurizingsheet 344 has a radially outer edge clamped between the housing 316 aand the pressurizing sheet support 316 b of the top ring body 316, and aradially inner edge clamped between an upper portion 340 a and a stopper340 b of the holder ring 340. The top ring body 316, the chucking plate342, the holder ring 340, and the pressurizing sheet 344 jointly definea pressure chamber 346 in the top ring body 316. As shown in FIG. 10, afluid passage 348 comprising tubes and connectors communicates with thepressure chamber 346, which is connected to the compressed air source320 via a regulator R2 connected to the fluid passage 348. Thepressurizing sheet 344 is made of a highly strong and durable rubbermaterial such as ethylene propylene rubber (ethylene-propyleneterpolymer (EPDM)), polyurethane rubber, silicone rubber, or the like.

In the case of a pressurizing sheet 344 made of an elastic material suchas rubber, if the pressurizing sheet 344 is clamped between the retainerring 318 and the top ring body 316, then the pressurizing sheet 344 iselastically deformed as an elastic material, and a desired horizontalsurface cannot be maintained on the lower surface of the retainer ring318. In order to maintain the desired horizontal surface on the lowersurface of the retainer ring 318, the pressurizing sheet 344 is clampedbetween the housing 316 a of the top ring body 316 and the pressurizingsheet support 316 b provided as a separate member in the presentembodiment. The retainer ring 318 may vertically be movable with respectto the top ring body 316, or the retainer ring 318 may have a structurecapable of pressing the polishing surface independently of the top ringbody 316. In such cases, the pressurizing sheet 344 is not necessarilyfixed in the aforementioned manner.

A cleaning liquid passage 350 in the form of an annular groove isdefined in the upper surface of the housing 316 a near its outercircumferential edge over which the seal 316 c is fitted. The cleaningliquid passage 350 communicates with a fluid passage 354 via a throughhole 352 formed in the seal 316 c, and is supplied with a cleaningliquid (pure water) via the fluid passage 354. A plurality ofcommunication holes 356 are defined in the housing 316 a and thepressurizing sheet support 316 b in communication with the cleaningliquid passage 350. The communication holes 356 communicate with a smallgap G defined between the outer circumferential surface of the elasticpad 336 and the inner circumferential surface of the retainer ring 318.The fluid passage 354 is connected to a cleaning liquid source (notshown) through a rotary joint (not shown).

The space defined between the elastic pad 336 and the chucking plate 342accommodates therein a central bag 360 as a central contact memberbrought into contact with the elastic pad 336, and a ring tube 362 as anouter contact member brought into contact with the elastic pad 336.These contact members may be brought into abutment against the elasticpad 336. In the present embodiment, as shown in FIGS. 10 and 11, thecentral bag 360 having a circular contact surface is disposed centrallyon the lower surface of the chucking plate 342, and the ring tube 362having an annular contact surface is disposed radially outwardly of thecentral bag 360 in surrounding relation thereto. Specifically, thecentral bag 360 and the ring tube 362 are spaced at predeterminedintervals. Each of the elastic pad 336 and the central bag 360 and thering tube 362 is made of a highly strong and durable rubber materialsuch as ethylene propylene rubber (ethylene-propylene terpolymer(EPDM)), polyurethane rubber, silicone rubber, or the like.

The space defined between the chucking plate 342 and the elastic pad 336is divided into a plurality of spaces (second pressure chambers) by thecentral bag 360 and the ring tube 362. Specifically, a pressure chamber364 is defined between the central bag 360 and the ring tube 362, and apressure chamber 366 is defined radially outwardly of the ring tube 362.

The central bag 360 comprises an elastic membrane 368 brought intocontact with the upper surface of the elastic pad 336, and a central bagholder (holding member) 370 for detachably holding the elastic membrane368 in position. The central bag holder 370 has threaded holes 370 adefined therein, and is detachably fastened to the center of the lowersurface of the chucking plate 342 by screws 372 threaded into thethreaded holes 370 a. The central bag 360 has a central pressure chamber374 (first pressure chamber) defined therein by the elastic membrane 368and the central bag holder 370.

Similarly, the ring tube 362 comprises an elastic membrane 376 broughtinto contact with the upper surface of the elastic pad 336, and a ringtube holder (holding member) 378 for detachably holding the elasticmembrane 376 in position. The ring tube holder 378 has threaded holes378 a defined therein, and is detachably fastened to the lower surfaceof the chucking plate 342 by screws 380 threaded into the threaded holes378 a. The ring tube 362 has an intermediate pressure chamber 382 (firstpressure chamber) defined therein by the elastic membrane 376 and thering tube holder 378.

Fluid passages 384, 386, 388 and 390 comprising tubes and connectorscommunicate with the pressure chambers 364, 366, the central pressurechamber 374, and the intermediate pressure chamber 382, respectively.The pressure chambers 364, 366, 374 and 382 are connected to thecompressed air source 320 via respective regulators R3, R4, R5 and R6connected respectively to the fluid passages 384, 386, 388 and 390. Thefluid passages 348, 384, 386, 388 and 390 are connected to therespective regulators R2, R3, R4, R5 and R6 through a rotary joint (notshown) mounted on the upper end of the top ring drive shaft 310.

The pressure chamber 346, 364, 366, 374 and 382 are supplied with apressurized fluid such as pressurized air or atmospheric air orevacuated, via the fluid passages 348, 384, 386, 388 and 390. As shownin FIG. 9, the regulators R2 to R6 connected to the fluid passages 348,384, 386, 388 and 390 of the pressure chambers 346, 364, 366, 374 and382 can respectively regulate the pressures of the pressurized fluidssupplied to the pressure chambers 346, 364, 366, 374 and 382, forthereby independently controlling the pressures in the pressure chambers346, 364, 366, 374 and 382 or independently introducing atmospheric airor vacuum into the pressure chambers 346, 364, 366, 374 and 382. Thus,the pressures in the pressure chambers 346, 364, 366, 374 and 382 areindependently varied with the regulators R2 to R6, so that the pressingforces, which are pressures per unit area for pressing the substrate Wagainst the polishing pad 302, can be adjusted in local areas of thesubstrate W via the elastic pad 336. In some applications, the pressurechambers 346, 364, 366, 374 and 382 may be connected to a vacuum source392.

In this case, the pressurized fluid or the atmospheric air supplied tothe pressure chambers 364, 366, 374 and 382 may independently becontrolled in temperature, for thereby directly controlling thetemperature of the substrate from the backside of the surface to bepolished. Particularly, when each of the pressure chambers isindependently controlled in temperature, the rate of chemical reactioncan be controlled in the chemical polishing process of CMP.

As shown in FIG. 11, a plurality of openings 400 are formed in theelastic pad 336. The chucking plate 342 has radially inner suctionportions 402 and radially outer suction portions 404 extended downwardlytherefrom. The openings 400 positioned between the central bag 360 andthe ring tube 362 allow the inner suction portions 402 to be exposedexternally, and the openings 400 positioned outside of the ring tube 362allow the outer suction portions 404 to be exposed externally. In thepresent embodiment, the elastic pad 336 has eight openings 400 forallowing the eight suction portions 402, 404 to be exposed.

Each of the inner suction portions 402 has a hole 402 a communicatingwith a fluid passage 406, and each of the outer suction portions 404 hasa hole 404 a communicating with a fluid passage 408. Thus, the innersuction portion 402 and the outer suction portion 404 are connected tothe vacuum source 392 such as a vacuum pump via the respective fluidpassages 406, 408 and valves V1, V2. When the suction portions 402, 404are evacuated by the vacuum source 392 to develop a negative pressure atthe lower opening ends of the communicating holes 402 a, 404 a thereof,a substrate W is attracted to the lower ends of the suction portions402, 404 by the negative pressure. The suction portions 402, 404 haveelastic sheets 402 b, 404 b, such as thin rubber sheets, attached totheir lower ends, for thereby elastically contacting and holding thesubstrate W on the lower surfaces thereof.

As shown in FIG. 10, when the substrate W is polished, the lower ends ofthe suction portions 402, 404 are positioned above the lower surface ofthe elastic pad 336, without projecting downwardly from the lowersurface of the elastic pad 336. When the substrate W is attracted to thesuction portions 402, 404, the lower ends of the suction portions 402,404 are positioned at the same level as the lower surface of the elasticpad 336.

Since there is the small gap G between the outer circumferential surfaceof the elastic pad 336 and the inner circumferential surface of theretainer ring 318, the holder ring 340, the chucking plate 342, and theelastic pad 336 attached to the chucking plate 342 can vertically bemoved with respect to the top ring body 316 and the retainer ring 318,and hence are of a floating structure with respect to the top ring body316 and the retainer ring 318. A plurality of teeth 340 c projectradially outwardly from the outer circumferential edge of the stopper340 b of the holder ring 340. When the teeth 340 c engage the uppersurface of the radially inwardly projecting portion of the retainer ring318 upon downward movement of the holder ring 340, the holder ring 340is limited against any further downward movement.

Operation of the top ring 300 thus constructed will be described below.

When the substrate W is to be delivered to the polishing apparatus, thetop ring 300 is moved to a position to which the substrate W istransferred, and the communicating holes 402 a, 404 a of the suctionportions 402, 404 are evacuated via the fluid passages 406, 408 by thevacuum source 392. The substrate W is attracted to the lower ends of thesuction portions 402, 404 by suction effect of the communicating holes402 a, 404 a. With the substrate W attracted to the top ring 300, thetop ring 300 is moved to a position above the polishing table 304 havingthe polishing surface (polishing pad 302) thereon. The retainer ring 318holds the outer circumferential edge of the substrate W so that thesubstrate W is not removed from the top ring 300.

For polishing the lower surface of the substrate W, the substrate W isthus held on the lower surface of the top ring 300, and the top ring aircylinder 314 connected to the top ring drive shaft 310 is actuated topress the retainer ring 318 fixed to the lower end of the top ring 300against the polishing surface on the polishing table 304 under apredetermined pressure. Then, the pressurized fluids are respectivelysupplied to the pressure chambers 364, 366, the central pressure chamber374, and the intermediate pressure chamber 382 under respectivepressures, thereby pressing the substrate W against the polishingsurface on the polishing table 304. The polishing liquid supply nozzle306 then supplies the polishing liquid Q onto the polishing pad 302.Thus, the substrate W is polished by the polishing pad 302 with thepolishing liquid Q being present between the lower surface, to bepolished, of the substrate W and the polishing pad 302.

The local areas of the substrate W that are positioned beneath thepressure chambers 364, 366 are pressed against the polishing pad 302under the pressures of the pressurized fluids supplied to the pressurechambers 364, 366. The local area of the substrate W that is positionedbeneath the central pressure chamber 374 is pressed via the elasticmembrane 368 of the central bag 360 and the elastic pad 336 against thepolishing pad 302 under the pressure of the pressurized fluid suppliedto the central pressure chamber 374. The local area of the substrate Wthat is positioned beneath the intermediate pressure chamber 382 ispressed via the elastic membrane 376 of the ring tube 362 and theelastic pad 336 against the polishing pad 302 under the pressure of thepressurized fluid supplied to the intermediate pressure chamber 382.

Therefore, the polishing pressures acting on the respective local areasof the substrate W can be adjusted independently by controlling thepressures of the pressurized fluids supplied to each of the pressurechambers 364, 366, 374 and 382. Specifically, each of the regulators R3to R6 independently regulates the pressure of the pressurized fluidsupplied to the pressure chambers 364, 366, 374 and 382 for therebyadjusting the pressing forces applied to press the local areas of thesubstrate W against the polishing pad 302 on the polishing table 304.With the polishing pressures on the respective local areas of thesubstrate W being adjusted independently, the substrate W is pressedagainst the polishing pad 302 on the polishing table 304 that is beingrotated. Similarly, the pressure of the pressurized fluid supplied tothe top ring air cylinder 314 can be regulated by the regulator R1 toadjust the force with which the retainer ring 318 presses the polishingpad 302. While the substrate W is being polished, the force with whichthe retainer ring 318 presses the polishing pad 302 and the pressingforce with which the substrate W is pressed against the polishing pad302 can appropriately be adjusted for thereby applying polishingpressures in a desired pressure distribution to a central area C1, aninner area C2, an intermediate area C3, and a peripheral area C4 of thesubstrate W (see FIG. 11).

The local areas of the substrate W that are positioned beneath thepressure chambers 364, 366 are divided into areas to which a pressingforce from a fluid is applied via the elastic pad 336, and areas towhich the pressure of a pressurized fluid is directly applied, such asareas positioned beneath the openings 400. However, the pressing forcesapplied to these two areas are equal to each other. When the substrate Wis polished, the elastic pad 336 is brought into close contact with theupper surface of the substrate W near the openings 400, so that thepressurized fluids supplied to the pressure chambers 364, 366 areprevented from flowing out to the exterior.

In this manner, the substrate W is divided into the concentric circularand annular areas C1 to C4, which can be pressed under independentpressing forces. The polishing rates of the circular and annular areasC1 to C4, which depend on the pressing forces applied to those areas,can independently be controlled because the pressing forces applied tothose areas can independently be controlled. Consequently, even if thethickness of a thin film to be polished on the surface of the substrateW suffers radial variations, the thin film on the surface of thesubstrate W can be polished uniformly without being insufficiently orexcessively polished. More specifically, even if the thickness of thethin film to be polished on the surface of the substrate W differsdepending on the radial position on the substrate W, the pressure in apressure chamber positioned over a thicker area of the thin film is madehigher than the pressure in a pressure chamber positioned over a thinnerarea of the thin film, or the pressure in a pressure chamber positionedover a thinner area of the thin film is made lower than the pressure ina pressure chamber positioned over a thicker area of the thin film. Inthis manner, the pressing force applied to the thicker area of the thinfilm is made higher than the pressing force applied to the thinner areaof the thin film, thereby selectively increasing the polishing rate ofthe thicker area of the thin film. Consequently, the entire surface ofthe substrate W can be polished exactly to a desired level irrespectiveof the film thickness distribution obtained at the time the thin film isformed.

Any unwanted edge rounding on the circumferential edge of the substrateW can be prevented by controlling the pressing force applied to theretainer ring 318. If the thin film to be polished on thecircumferential edge of the substrate W has large thickness variations,then the pressing force applied to the retainer ring 318 isintentionally increased or reduced to thus control the polishing rate ofthe circumferential edge of the substrate W. When the pressurized fluidsare supplied to the pressure chambers 364, 366, 374 and 382, thechucking plate 342 is subjected to upward forces. In the presentembodiment, the pressurized fluid is supplied to the pressure chamber346 via the fluid passage 348 to prevent the chucking plate 342 frombeing lifted under the forces from the pressure chambers 364, 366, 374and 382.

As described above, the pressing force applied by the top ring aircylinder 314 to press the retainer ring 318 against the polishing pad302 and the pressing forces applied by the pressurized fluids suppliedto the pressure chambers 364, 366, 374 and 382 to press the local areasof the substrate W against the polishing pad 302 are appropriatelyadjusted to polish the substrate W. When the polishing of the substrateW is finished, the substrate W is attracted to the lower ends of thesuction portions 402, 404 under vacuum in the same manner as describedabove. At this time, the supply of the pressurized fluids into thepressure chambers 364, 366, 374 and 382 is stopped, and the pressurechambers 364, 366, 374 and 382 are vented to the atmosphere.Accordingly, the lower ends of the suction portions 402, 404 are broughtinto contact with the substrate W. The pressure chamber 346 is vented tothe atmosphere or evacuated to develop a negative pressure therein. Ifthe pressure chamber 346 is maintained at a high pressure, then thesubstrate W is strongly pressed against the polishing surface only inareas brought into contact with the suction portions 402, 404.Therefore, it is necessary to decrease the pressure in the pressurechamber 346 immediately. Accordingly, a relief port 410 penetratingthrough the top ring body 316 may be provided for decreasing thepressure in the pressure chamber 346 immediately, as shown in FIG. 10.In this case, when the pressure chamber 346 is pressurized, it isnecessary to continuously supply the pressurized fluid into the pressurechamber 346 via the fluid passage 348. The relief port 410 comprises acheck valve (not shown) for preventing an outside air from flowing intothe pressure chamber 346 at the time when a negative pressure isdeveloped in the pressure chamber 346.

After the substrate W is attracted to the lower ends of the suctionportions 402, 404, the entire top ring 300 is moved to a position towhich the substrate W is to be transferred. Then, a fluid such ascompressed air or a mixture of nitrogen and pure water is ejected to thesubstrate W via the communicating holes 402 a, 404 a of the suctionportions 402, 404 to release the substrate W from the top ring 300.

The polishing liquid Q used to polish the substrate W tends to flowthrough the gap G between the outer circumferential surface of theelastic pad 336 and the retainer ring 318. If the polishing liquid Q isfirmly deposited in the gap G, then the holder ring 340, the chuckingplate 342, and the elastic pad 336 are prevented from smoothly movingvertically with respect to the top ring body 316 and the retainer ring318. To avoid such a drawback, a cleaning liquid (pure water) issupplied through the fluid passage 354 to the cleaning liquid passage350. Accordingly, the pure water is supplied via the communication holes356 to a region above the gap G, thus cleaning members defining the gapG to remove deposits of the polishing liquid Q. The pure water shouldpreferably be supplied after the polished substrate W is released anduntil a next substrate to be polished is attracted to the top ring 300.It is also preferable to discharge all the supplied pure water out ofthe top ring 300 before the next substrate is polished, and hence toprovide the retainer ring 318 with a plurality of through holes 318 ashown in FIG. 10 for discharging the pure water. Furthermore, if apressure buildup is developed in a space 412 defined between theretainer ring 318, the holder ring 340, and the pressurizing sheet 344,then it acts to prevent the chucking plate 342 from being elevated inthe top ring body 316. Therefore, in order to allow the chucking plate342 to be elevated smoothly in the top ring body 316, the through holes318 a should preferably be provided for equalizing the pressure in thespace 412 with the atmospheric pressure.

As described above, according to the embodiment, the pressures in thepressure chambers 364, 366, the pressure chamber 374 in the central bag360, and the pressure chamber 382 in the ring tube 362 are independentlycontrolled to control the pressing forces acting on the substrate W.Further, according to the embodiment, regions in which a pressing forceapplied to the substrate W is controlled can easily be changed bychanging positions or sizes of the central bag 360 and the ring tube362. Examples of changing the regions in which the pressing forceapplied to the substrate W is controlled will be described below.

FIGS. 12A through 12E and FIG. 13 are vertical cross-sectional viewsshowing other examples of the contact members (central bag 360 and ringtube 362) in the substrate holder of a CMP device.

As shown in FIGS. 12A and 12B, the area C1 in which the pressing forceapplied to the substrate is controlled can be changed by another centralbag 360 having a different size. In this case, when the size and shapeof a hole 370 b for allowing the pressure chamber 374 defined in thecentral bag 360 to communicate with the fluid passage 388, and the sizeand position of the threaded holes 370 a for mounting the central bagholder 370 on the chucking plate 342 are predetermined, the range inwhich the pressing force applied to the substrate is controlled can bechanged simply by preparing a central bag holder 370 having a differentsize. In this case, it is not necessary to modify the chucking plate342.

As shown in FIGS. 12C and 12D, the width and/or position of the area C3in which the pressing force applied to the substrate is controlled canbe changed by another ring tube 362 having a different size and/orshape. Further, as shown in FIG. 12E, a plurality of holes 414 andthreaded holes (not shown) may be provided in predetermined radialpositions of the chucking plate 342. In this case, the communicatinghole 378 b is positioned at a position corresponding to one of thecommunicating holes 414, and the other communicating holes (and threadedholes) are filled with screws 416 for sealing fluids. Thus, the ringtube 362 can flexibly be mounted in the radial direction, so that theregion in which the pressing force is controlled can flexibly bechanged.

As shown in FIG. 13, a protrusion 368 a protruding radially outwardlyfrom the circumferential edge of the elastic membrane 368 may beprovided on the lower surface of the central bag 360, and protrusions376 a protruding radially from the circumferential edges of the elasticmembrane 376 may be provided on the lower surface of the ring tube 362.The protrusions 368 a, 376 a are made of the same material as thecentral bag 360 and the ring tube 362. As described above, when thesubstrate is polished, pressurized fluids are supplied to the pressurechamber 364 positioned between the central bag 360 and the ring tube362, and the pressure chamber 366 surrounding the ring tube 362.Therefore, the protrusions 368 a, 376 a are brought into close contactwith the elastic pad 336 by the pressurized fluids supplied to thepressure chambers 364, 366. Thus, even if the pressure of thepressurized fluid supplied to the pressure chamber 364 adjacent to thecentral bag 360 is considerably higher than the pressure of thepressurized fluid supplied to the pressure chamber 374 defined in thecentral bag 360, the high-pressure fluid adjacent to the central bag 360is prevented from flowing into the lower portion of the central bag 360.Similarly, even if the pressure of the pressurized fluid supplied to thepressure chamber 364 or 366 adjacent to the ring tube 362 isconsiderably higher than the pressure of the pressurized fluid suppliedto the pressure chamber 382 defined in the ring tube 362, thehigh-pressure fluid adjacent to the ring tube 362 is prevented fromflowing into the lower portion of the ring tube 362. Therefore, theprotrusions 368 a, 376 a can widen the range of pressure control in eachof the pressure chambers, for thereby pressing the substrate morestably.

The elastic membrane 368, 376 may have a partially different thicknessor may partially include an inelastic member, so that deformations ofthe elastic membrane 368 of the central bag 360 and of the elasticmembrane 376 of the ring tube 362 are ideal. FIG. 14A shows an examplein which the elastic membrane 376 of the ring tube 362 has side surfaces376 b thicker than the surface brought into contact with the elastic pad336. FIG. 14B shows an example in which the elastic membrane 376 of thering tube 362 partially includes inelastic members 376 d in the sidesurfaces thereof. In these examples, deformation of the side surfaces ofthe elastic membrane due to the pressure in the pressure chambers canappropriately be limited.

As described above, the distribution of the thin film formed on thesurface of the substrate varies depending on a deposition method or adeposition apparatus. According to the embodiment, a substrate holdingapparatus can change the position and size of the pressure chambers forapplying the pressing force to the substrate simply by change of thecentral bag 360 and the central bag holder 370, or the ring tube 362 andthe ring tube holder 378. Therefore, the position and region in whichthe pressing force is controlled can easily be changed in accordancewith the distribution of the thin film to be polished at low cost. Inother words, the substrate holder can cope with various thicknessdistributions of the thin film formed on the substrate to be polished.The change of the shape and position of the central bag 360 or the ringtube 362 leads to the change of the size of the pressure chamber 364positioned between the central bag 360 and the ring tube 362, and thepressure chamber 366 surrounding the ring tube 362.

FIG. 15 is a vertical cross-sectional view showing an another top ring300 of a CMP device. The top ring 300 has a seal ring 420 instead of anelastic pad. The seal ring 420 comprises an elastic membrane coveringonly a lower surface of a chucking plate 342 near its outercircumferential edge. In this embodiment, neither an inner suctionportion (indicated by the reference numeral 402 in FIG. 10) nor an outersuction portion (indicated by the reference numeral 402 in FIG. 10) isprovided on the chucking plate 342, for a simple configuration. However,suction portions for attracting a substrate may be provided on thechucking plate 342, as described above. The seal ring 420 is made of ahighly strong and durable rubber material such as ethylene propylenerubber (ethylene-propylene terpolymer (EPDM)), polyurethane rubber,silicone rubber, or the like.

The seal ring 420 is provided in such a state that the lower surface ofthe seal ring 420 is brought into contact with the upper surface of thesubstrate W. The seal ring 420 has a radially outer edge clamped betweenthe chucking plate 342 and a holder ring 340. The substrate W has arecess defined in an outer edge thereof, which is referred to as a notchor orientation flat, for recognizing or identifying the orientation ofthe substrate. Therefore, the seal ring 420 should preferably extendradially inwardly from the innermost position of the recess such a notchor orientation flat.

A central bag 360 is disposed centrally on the lower surface of thechucking plate 342, and a ring tube 362 is disposed radially outwardlyof the central bag 360 in surrounding relation thereto, as withdescribed above.

In this embodiment, a substrate W to be polished is held by the top ring300 in such a state that the substrate W is brought into contact withthe seal ring 420, an elastic membrane 368 of the central bag 360, andan elastic membrane 376 of the ring tube 362. Therefore, the substrate Wthe chucking plate 342, and the seal ring 420 jointly define a spacetherebetween. This space is divided into a plurality of spaces (secondpressure chambers) by the central bag 360 and the ring tube 362.Specifically, a pressure chamber 364 is defined between the central bag360 and the ring tube 362, and a pressure chamber 366 is definedradially outwardly of the ring tube 362.

Fluid passages 384, 386, 388 and 390 comprising tubes and connectorscommunicate with the pressure chambers 364, 366, a central pressurechamber (first pressure chamber) 374 defined in the central bag 360, andan intermediate pressure chamber (first pressure chamber) 382 defined inthe ring tube 362, respectively. The pressure chambers 364, 366, 374 and382 are connected to the compressed air source via respective regulatorsconnected respectively to the fluid passages 384, 386, 388 and 390. Theregulators connected to the fluid passages 348, 384, 386, 388 and 390 ofthe pressure chambers 346, 364, 366, 374 and 382 can respectivelyregulate the pressures of the pressurized fluids supplied to thepressure chambers 346, 364, 366, 374 and 382, for thereby independentlycontrolling the pressures in the pressure chambers 346, 364, 366, 374and 382 or independently introducing atmospheric air or vacuum into thepressure chambers 346, 364, 366, 374 and 382. Thus, the pressures in thepressure chambers 346, 364, 366, 374 and 382 are independently variedwith the regulators, so that the pressing forces can be adjusted inlocal areas of the substrate W. In some applications, the pressurechambers 346, 364, 366, 374 and 382 may be connected to a vacuum source392.

Operation of the top ring 300 thus constructed will be described below.

When the substrate W is to be delivered to the polishing apparatus, thetop ring 300 is moved to a position to which the substrate W isdelivered, and the central bag 360 and the ring tube 362 are suppliedwith a pressurized fluid under a predetermined pressure for bringing thelower surfaces of the central bag 360 and the ring tube 362 into closecontact with the upper surface of the substrate W. Thereafter, thepressure chambers 364, 366 are connected to a vacuum source via thefluid passages 384, 386 to develop a negative pressure in the pressurechambers 364, 366 for thereby attracting the substrate W under vacuum.

For polishing the lower surface of the substrate W, the substrate W isthus held on the lower surface of the top ring 300, and the top ring aircylinder 314 connected to the top ring drive shaft 310 is actuated topress the retainer ring 318 fixed to the lower end of the top ring 300against the polishing surface on the polishing table 304 under apredetermined pressure. Then, the pressurized fluids are respectivelysupplied to the pressure chambers 364, 366, the central pressure chamber374, and the intermediate pressure chamber 382 under respectivepressures, thereby pressing the substrate W against the polishingsurface on the polishing table 304. The polishing liquid supply nozzle306 then supplies the polishing liquid Q onto the polishing pad 302.Thus, the substrate W is polished by the polishing pad 302 with thepolishing liquid Q being present between the lower surface, to bepolished, of the substrate W and the polishing pad 302.

The local areas of the substrate W that are positioned beneath thepressure chambers 364, 366 are pressed against the polishing pad 302under the pressures of the pressurized fluids supplied to the pressurechambers 364, 366. The local area of the substrate W that is positionedbeneath the central pressure chamber 374 is pressed via the elasticmembrane 368 of the central bag 360 against the polishing pad 302 underthe pressure of the pressurized fluid supplied to the central pressurechamber 374. The local area of the substrate W that is positionedbeneath the intermediate pressure chamber 382 is pressed via the elasticmembrane 376 of the ring tube 362 against the polishing pad 302 underthe pressure of the pressurized fluid supplied to the intermediatepressure chamber 382.

Therefore, the polishing pressures acting on the respective local areasof the substrate W can be adjusted independently by controlling thepressures of the pressurized fluids supplied to each of the pressurechambers 364, 366, 374 and 382. Thus, the substrate W is divided intothe concentric circular and annular areas, which can be pressed underindependent pressing forces. The polishing rates of the circular andannular areas, which depend on the pressing forces applied to thoseareas, can independently be controlled because the pressing forcesapplied to those areas can independently be controlled. Consequently,even if the thickness of a thin film to be polished on the surface ofthe substrate W suffers radial variations, the thin film on the surfaceof the substrate W can be polished uniformly without beinginsufficiently or excessively polished. More specifically, even if thethickness of the thin film to be polished on the surface of thesubstrate W differs depending on the radial position on the substrate W,the pressure in a pressure chamber positioned over a thicker area of thethin film is made higher than the pressure in a pressure chamberpositioned over a thinner area of the thin film, or the pressure in apressure chamber positioned over a thinner area of the thin film is madelower than the pressure in a pressure chamber positioned over a thickerarea of the thin film. In this manner, the pressing force applied to thethicker area of the thin film is made higher than the pressing forceapplied to the thinner area of the thin film, thereby selectivelyincreasing the polishing rate of the thicker area of the thin film.Consequently, the entire surface of the substrate W can be polishedexactly to a desired level irrespective of the film thicknessdistribution obtained at the time the thin film is formed.

When the substrate W is polished, the seal ring 420 is brought intoclose contact with a part of the upper surface of the substrate forthereby sealing this space. Hence, the pressurized fluid is preventedfrom flowing out to the exterior of the pressure chamber 366.

When the polishing of the substrate W is finished, the substrate W isattracted under vacuum in the same manner as described above, and thenthe pressure chamber 346 is vented to the atmosphere or evacuated todevelop a negative pressure therein. After the substrate W is attracted,the entire top ring 300 is moved to a position from which the substrateW is to be delivered. Then, a fluid such as compressed air or a mixtureof nitrogen and pure water is ejected to the substrate W via the fluidpassages 384, 386 to release the substrate W from the top ring 300. Ifthe elastic membrane 368 of the central bag 360 and the elastic membrane376 of the ring tube 362 have through holes defined in their lowersurfaces, then since downward forces are applied to the substrate W bythe fluid flowing through these through holes, the substrate W can besmoothly released from the top ring 300. After the substrate W isreleased from the top ring 300, most of the lower surface of the topring 300 is exposed. Therefore, the lower surface of the top ring 300can be cleaned relatively easily after the substrate W is polished andreleased.

In the embodiments described above, the fluid passages 348, 384, 386,388 and 390 are provided as separate passages. However, the arrangementof the fluid passages and the pressure chambers may be modified inaccordance with the magnitude of the pressing force to be applied to thesubstrate W and the position to which the pressing force is applied. Forexample, these passages may be joined to each other, or the pressurechambers may be connected to each other.

The pressure chambers 364, 366 may be connected to the pressure chamber346 to form one pressure chamber, without the fluid passage 384communicating with the pressure chamber 364 and the fluid passage 386communicating with the pressure chamber 366. In this case, the pressuresin the pressure chambers 346, 364, 366 are controlled at an equalpressure by a pressurized fluid supplied via the fluid passage 348. Ifit is not necessary to provide a pressure difference between thepressure chamber 364 and the pressure chamber 366, and the pressures inthe central pressure chamber 374 and the intermediate pressure chamber382 are not larger than the pressures in the pressure chambers 346, 364,366, then the above arrangement can be adopted to dispense with thefluid passages 384, 386, for thereby decreasing the number of the fluidpassages and simplifying the fluid passages.

When the inner suction portions 402 and the outer suction portions 404are provided on the chucking plate 342, as shown in FIGS. 10 and 11, notonly a vacuum is created in the fluid passages 406, 408 communicatingwith the suction portions 402, 404, but also pressurized fluids may besupplied to the fluid passages 406, 408. In this case, suction of thesubstrate in the suction portions 402, 404 and supply of the pressurizedfluids to the pressure chambers 364, 366 can be performed with onerespective passage. Hence, it is not necessary to provide two fluidpassages, i.e., the fluid passages 384, 386, for thereby decreasing thenumber of the fluid passages and simplifying the fluid passages.

The chucking plate 342 has a protuberance 422 projecting downwardly fromthe outer circumferential edge thereof for maintaining the shape of thelower peripheral portion of the elastic membrane 336 or the seal ring420 (see FIGS. 10 and 15). However, if it is not necessary to maintainthe shape of the elastic membrane 336 or the seal ring 420 because ofits material or the like, then the chucking plate 342 does not need tohave such a protuberance. FIG. 16 is a vertical cross-sectional viewshowing a top ring 300 in which the chucking plate 342 has noprotuberance 422 in the embodiment shown in FIGS. 10 and 11. In thiscase, the substrate W can uniformly-be pressed from the central portionthereof to the outer peripheral portion thereof. Further, the substratecan easily follow the large waviness or undulation on the polishingsurface by omitting the protuberance 422.

In the embodiments described above, the polishing surface is constitutedby the polishing pad. However, the polishing surface is not limited tothis. For example, the polishing surface may be constituted by a fixedabrasive. The fixed abrasive is formed into a flat plate comprisingabrasive particles fixed by a binder. With the fixed abrasive, thepolishing process is performed by the abrasive particles self-generatedfrom the fixed abrasive. The fixed abrasive comprises abrasiveparticles, a binder, and pores. For example, cerium dioxide (CeO₂)having an average particle diameter of 0.5 μm is used as an abrasiveparticle, and epoxy resin is used as a binder. Such a fixed abrasiveforms a harder polishing surface. The fixed abrasive includes a fixedabrasive pad having a two-layer structure formed by a thin layer of afixed abrasive and an elastic polishing pad attached to the layer of thefixed abrasive. IC-1000 described above may be used for another hardpolishing surface.

FIGS. 17 and 18 show an example of the substrate transport box 24 inwhich the substrate cassette 22 accommodating the substrates W with theexposed copper film on the surface thereof is housed and sealed up, andthe substrates W in the enclosed state are transported together with thesubstrate cassette 22. The substrate transport box 24 comprises generalSMIF or HOOP. A particle removal filter and a fan motor may be installedwithin the substrate transport box 24 to circulate and purify the gasinside the substrate transport box 24, whereby cross contaminationbetween the substrates can be prevented. Also, particles and ions can beremoved by installing both of a chemisorption filter and a particlefilter inside the substrate transport box 24. Of course, only a particlefilter, and a deionization filter as a chemical filter may be used. Whena fan motor, etc. are installed in the substrate transport box 24, it ispermissible to flow an electric current from a socket-outlet provided ina base member or the like when the substrate transport box 24 is mountedon the base member or the like, thereby rotating the fan motor, insteadof providing batteries inside the substrate transport box 24.

Furthermore, the occurrence of an oxide film can be prevented byproviding dehumidification means, such as a dehumidifying agent, in thesubstrate transport box 24 to control the humidity inside the substratetransport box 24. In this case, the humidity inside the substratetransport box 24 is decreased, preferably, to 10% or less, and morepreferably, to 5% or less. If there is a possibility for destruction ofthe semiconductor device by generation of static electricity at a lowhumidity, it is desirable that the copper surface of each substrate begrounded to allow the static electricity to escape while the substrateis transported and/or stored.

The interior of the substrate transport box 24 is normally filled withair, but the use of an inert gas or the like with a restricted amount ofoxygen can prevent oxidation of copper. The amount of oxygen ispreferably 10,000 ppm or less, more preferably 1,000 ppm or less.

FIGS. 19 to 22 show other example of the substrate transport box 24.This substrate transport box 24, for example, serves to transport andstore a plurality of 300 mm substrates W accommodated in groove-shapedpockets 504 fixed to the inside of a box body 501. The substratetransport box 24 comprises a rectangular tubular box body 501, asubstrate carry-in/carry-out door 502 for mechanically opening/closingan opening portion formed in a side surface of the box body 501 byconnected to a substrate carry-in/carry-out door automaticopening/closing device, a closure 503 located on a side opposite to theopening portion and adapted to cover an opening for mounting anddismounting filters and a fan motor, groove-shaped pockets 504 forholding substrates W, a ULPA filter 505, a chemical filter 506, and afan motor 507.

The substrate carry-in/carry-out door 502 can be opened and closedmechanically. V grooves 509 for engagement with kinematic coupling pins508 (see FIG. 23) for performing high accuracy positioning at thesubstrate carry-in/carry-out door automatic opening/closing device areprovided at the bottom of the box body 501. Positioning pin receivingportions 510, and accepting portions 511 into which latch keys foropening/closing the door are inserted are provided in the substratecarry-in/carry-out door 502 so that automatic opening/closing can bedone from the substrate carry-in/carry-out door automaticopening/closing device side. Also, a robotic handling flange 512 isprovided so that transport can be performed using a transport devicesuch as OHT (overhead hoist transport) or AGV (automatic guidedvehicle). The V grooves 509, positioning pin receiving portions 510,accepting portions 511 into which latch keys for opening/closing thedoor are inserted, robotic handling flange 512, and other mattersconcerned with automated interface are designed in compliance with SEMIStandards E1.9, E47.1, E57 and E62.

The interior of the box body 501 is partitioned into a central chamber513 a at the center, and a pair of side chambers 513 b located on bothsides of the central chamber 513 a, by a partition plate 530. Thepartition plate 530 integrated with the right and left groove-shapedpockets 504 as pairs is positioned to have gaps between the substratecarry-in/carry-out door 502 and the closure 503. The groove-shapedpockets 504 having taper portions fanning out toward the door so as toengage the substrates W are integrally provided in a portion of thepartition plate 530 facing the substrate carry-in/carry-out door 502.

In a portion of the central chamber 513 a facing the closure 503, theULPA filter 505 constituting a particle removing filter mainly intendedto remove particles, and the chemical filter 506 constituting a gaseousimpurities trapping filter for removing impurity gases are disposed suchthat air can flow from the closure 503 toward the substratecarry-in/carry-out door 502. Upstream from the trapping filter 506, thefan motor 507 is disposed so as to send air toward the substratecarry-in/carry-out door 502.

Opposite end portions of the substrate carry-in/carry-out door 502 arein an inwardly smoothly curved form, and a triangular stream regulatingplate 514 is provided at the center of the substrate carry-in/carry-outdoor 502. The substrate carry-in/carry-out door 502 is also equippedwith fixing jigs 515 for preventing displacement of the substrate.Similarly, an inner surface of the closure 503 is in an inwardly curvedform, and a triangular stream regulating plate 516 is provided at thecenter of the closure 503. Furthermore, stream regulating plates 517intended to supply clean air uniformly to the plurality of substrates Ware mounted at two locations adjacent to the inward clean air supplyopening.

When 25 of the substrates W are accommodated, for example, the gapbetween each of the first and twenty-fifth substrates W and the innerwall surface of the substrate transport box 24 is set to be wider thanthe spacing between the other adjacent substrates W. With thisarrangement, the supply of a uniform flow rate to the substrates W isinhibited, but the provision of the stream regulating plates 517 at theinward clean air supply opening uniformizes the flow rate between eachof the first and twenty-fifth substrates W and the carrier body relativeto the flow rate between the adjacent substrates, thereby performingpurification efficiently.

A power supply unit 518 incorporating a secondary battery is disposed atthe bottom of the closure 503, and has a contact for connection to aterminal 519 of the fan motor 507. An operation control substrate forthe fan motor 507 is incorporated in the power supply unit 518. The fanmotor 507 is controlled in terms of the timings of operation andstoppage and the number of rotations in compliance with control programswhich have been programmed in the control substrate. A charging terminal520 is provided at the bottom of the power supply unit 518. When thesubstrate transport box 24 is seated on the substrate carry-in/carry-outdoor automatic opening/closing device or on a charging station, thecharging terminal 520 is connected to the terminal present in thisdevice, whereby the secondary battery can be charged automatically.

The gaseous impurities trapping filter 506, in the present embodiment,is constituted by wrapping particulate activated carbon for organicsubstrate removal in an ion exchange unwoven fabric for inorganic ionsremoval. The medium may be pulverized activated carbon, activated carbonfibers, high purity silicon, zeolite, ceramic or impregnation activatedcarbon. The activated carbon fibers can be obtained by shaping rayon,kainol, polyacrylonitrile, petroleum, or petroleum pitch into a fibrousform, and subjecting the fibrous carbonaceous material to a so-calledactivation reaction, i.e., a gasification reaction with steam or carbondioxide at a high temperature of 800° C. or higher. The activated carbonfibers may contain a binder or the like, which does not contribute toadsorption, for the purpose of maintaining strength and preventing dustgeneration. However, a lower content of the binder or the like isdesirable as a material.

Activated carbon has many pores among the basic crystals, becauseunstructured carbon, etc. have-been removed during the process ofactivation. These pores and a large specific surface area impart highphysical adsorptivity to activated carbon. An activated carbon filterfilled with particulate activated carbon taking advantage of the aboveproperty is commercially available. Also on the market, as filmmaterials for an air filter are a filter comprising activated carbonfibers with little dust formation, high workability, finer pores thanparticulate activated carbon, and a large specific surface area, and afilter having particulate activated carbon of about 0.5 mm in diametercarried on a urethane foam of an open porous structure.

High purity silicon, the same material as that of the semiconductorsubstrate, can be used as an adsorbent. The surface state of high puritysilicon comes in two types, hydrophilic and hydrophobic, and thehydrophilic and hydrophobic ones are different in adsorption properties.Generally, the hydrophobic surface washed with dilute hydrofluoric acidis susceptible to environment, and shows high adsorbing propertiestoward hydrocarbon even at a very low concentration. However, thehydrophobic-surface silicon changes into a hydrophilic surface as anoxide film grows. Thus, the hydrophobic-surface silicon has the drawbackof the adsorption properties changing over time. The hydrophilic surfacehighly adsorbs an organic substance having polarity, for example, BHT(2,6-di-t-butyl-p-cresol) or DBP (dibutyl phthalate). Either high puritysilicon is effectively used not alone, but in combination with activatedcarbon.

The ion exchange unwoven fabric or fibers can be obtained, for example,by introducing ion exchange groups by a radiation graft polymerizationreaction. That is, a base material composed of an organic polymer, forexample, a polymer such as polyethylene or polypropylene, or a naturallyoccurring high molecular fiber or woven fabric, such as cotton or wool,is irradiated with radiation, such as electron rays or gamma rays, togenerate many active points. These active points have very highactivity, and are called radicals. A monomer is chemically bonded tothese radicals, whereby the properties of the monomer which aredifferent from the properties of the base material can be imparted.

This technique grafts the monomer to the base material, and thus iscalled graft polymerization. When a monomer having a sulfone group,carboxyl group, amino group or the like, which is an ion exchange group,for example, sodium styrenesulfonate, acrylic acid, or arylamine, isbonded to the polyethylene unwoven fabric base material by radiationgraft polymerization, there can be obtained an unwoven fabric type ionexchanger with a much higher ion exchange rate than ion exchange beadsusually called an ion exchange resin.

Similarly, a monomer capable of accepting an ion exchange group, such asstyrene, chloromethylstyrene, glycidyl methacrylate, acrylonitrile, oracrolein, may be radiation graft polymerized with the base material, andthen an ion exchange group may be introduced. In this case as well, anion exchanger can be prepared in the form of the base material.

For a filter medium of a ULPA filter or HEPA filter, glass fibers havebeen used. However, it has been found that glass fibers react with ahydrogen fluoride (HF) vapor used in the manufacturing process for asemiconductor device to produce BF₃, thus posing a problem. In recentyears, a ULPA filter and an HEPA filter using as a filter medium PTFE(polytetrafluoroethylene), which is free from impurities such as boronor metal and is unaffected by acids, alkalis, and organic solvents, havebeen marketed. Glass fibers or PTFE may be selected as the need arises.

Actions to be done when the substrate transport box 24 accommodating aplurality of substrates W is carried in the copper plating device 18shown in FIG. 1, for example, will be described with reference to FIG.23.

The copper plating device 18 has a substrate carry-in/carry-out doorautomatic opening/closing device. When the substrate transport box 24 istransported into the copper plating device 18, it is placed at apredetermined position. When the substrate transport box 24 is cut offfrom the clean room via a gate valve or the like, the substratecarry-in/carry-out door automatic opening/closing device opens thesubstrate carry-in/carry-out door 502. Then, the substrate W iswithdrawn by a substrate handling robot 521 within the plating device18, and processed. The substrate W after process is returned to thesubstrate transport box 24. After process of all the substrates W iscompleted, the substrate carry-in/carry-out door 502 is closed by thesubstrate carry-in/carry-out door automatic opening/closing device toseal up the substrate transport box 24. From this moment onward, anoperation of the fan motor 507 is started to purify air inside thesubstrate transport box 24. When the substrate carry-in/carry-out door502 is closed, the substrate transport box 24 is transported to asubsequent process or device, or a storage warehouse by OHT or AGV.

The fan motor 507 is operated in accordance with a preset program,whereby a flow of air from the fan motor 507 to the gaseous impuritiestrapping filter (chemical filter) 506, ULPA filter 505, and centralchamber 513 a occurs. Air flowing into the central chamber 513 a issmoothly bifurcated by the stream regulating plate 514 provided at thesubstrate carry-in/carry-out door 502, and the respective air streamspass through the side chambers 513 b and return to the fan motor 507. Inthis manner, a circulation path of air is formed.

Air is purified while being passed through the gaseous impuritiestrapping filter 506 and ULPA filter 505, and is then guided into thegaps among the substrates W by the inlet stream regulating plates 517positioned at the inside of the opening of the partition plate 530integrated with the groove-shaped pockets 504. By providing the inletstream regulating plates 517, air is prevented from excessively flowinginto the gaps between the substrates W and the partition plate 530integrated with the groove-shaped pockets 504. Air which has passedbetween the substrates W flows along the inner surfaces of the streamregulating plate 514 and the substrate carry-in/carry-out door 502,changes in direction to reverse, passes through the side chambers 513 b,and returns to the fan motor 507.

During this process, solid substances adhering to various parts, such asparticles, or gaseous substances resulting therefrom are carried by thecirculating air flow. The circulating air flow is purified by the twofilters 505 and 506 located upstream from the substrates W, and comes tothe substrates W. Thus, not only contamination from the outside, butalso so-called self-contamination with objects present inside thesubstrate transport box 24 is prevented.

The operation pattern of the fan motor 507 may be considered in suitablemodes adapted to the status of use of the substrate transport box 24.Generally, the operation is performed continuously or at a high flowvelocity in the initial stage to positively eliminate contaminationwhich has been brought into the substrate transport box 24. After acertain period of time elapses, the flow velocity is decreased, or theoperation is carried out intermittently to prevent contaminationoccurring from the substrates W housed in the substrate transfer box 24and the components installed inside the substrate transport box 24. Bythis classified operation, the electric power consumption of the fanmotor 507 can be decreased, with the result that the charging frequencyfor the secondary battery can be diminished.

When the substrate transport box 24 is set at a width W of 389.5 mm, adepth D of 450 mm, and a height H of 335 mm, and 25 of the substratesmeasuring 300 mm are housed in the substrate transport box 24, the totalweight including the substrates W is about 10 kg. In the presentembodiment, by actuating the fan motor 507, circulating air in an airvolume of 0.12 m³/min can be flowed in the substrate transport box 24 sothat the velocity of air passing through the center of the gap betweenthe substrates W will be 0.03 m/s. The circulating air volume can beincreased or decreased by changing the fan motor 507.

FIGS. 24 and 25 show still another example of the substrate transportbox 24. The differences of this example from the example shown in FIGS.19 to 22 are that the size of the substrate W is 200 mm, that a door 523for mechanical interface is located at the bottom of the box, and thatthe substrates W are housed in a substrate cassette 22 and, in thiscondition, accommodated in the substrate transport box 24. The method ofpurifying air in the substrate transport box 24 is the same as in theexample shown in FIGS. 19 to 22. In this example, a secondary batteryfor driving the fan motor 507 and a fan motor control circuit areincorporated in the box door 523.

When the substrate transport box 24 is set at a width W of 283 mm, adepth D of 342 mm, and a height H of 254 mm, and 25 of the substratesmeasuring 200 mm are housed in the substrate transport box 24, the totalweight including the substrates W and the substrate cassette 22 is about6 kg. In the present example, by actuating the fan motor 507,circulating air in an air volume of 0.05 m³/min can be flowed in thesubstrate transport box 24 so that the velocity of air passing throughthe center of the gap between the substrates W will be 0.03 m/s.

FIG. 26 shows the entire constitution of another substrate processingapparatus of the present invention. The copper film (plated copper film)6 shown in FIG. 62B is formed by use of a copper plating device 620having a film thickness distribution adjusting function. The thicknessof the copper film (plated copper film) 6 on the surface of thesubstrate is generally equal to or less than 2 micron meter, preferablyequal to or less than 1 micron meter. The film thickness distribution ofthe copper film 6 over the entire surface is measured with a filmthickness distribution measuring device 622. Chemical mechanicalpolishing is applied to the surface of the substrate by a polishingdevice (CMP device) 624 having a polishing amount adjusting function toform a copper interconnection composed of the copper film 6 as shown inFIG. 62C. For this procedure, based on the results of measurement by thefilm thickness distribution measuring device 622, control signals, suchas an electric field control signal and a plating time control signal,are inputted into the copper plating device 620 to control the copperplating device 620, and control signals, such as a press control signal,are inputted into the CMP device 624 to control the CMP device 624.

Details of the control are as follows: For the copper plating device620, the film thickness distribution of the copper film (plated copperfilm) 6 over the entire surface formed on the substrate is measured withthe film thickness distribution measuring device 622 making use of, forexample, the principle of eddy current thickness testing to find thedifference between the film thickness of the copper film (plated copperfilm) 6 at the center of the substrate and the film thickness on theperiphery of the substrate. Based on the results obtained, the copperplating device 620 is feedback controlled so that a plated copper filmwith a more uniform thickness will be deposited on the surface of thesubstrate to be processed after the target substrate measured, namely,that the difference between the film thickness of the plated copper filmat the center of the substrate and the film thickness on the peripheryof the substrate will be minimized. For the CMP device 624 as asubsequent processing step, the amounts of polishing at the center andon the periphery of the substrate are adjusted based on the results ofmeasurements of the film thickness distribution over the entire surface,for example, by adjusting the pressure imposed on the center and theperiphery of the substrate, whereby a flat copper film (plated copperfilm) 6 is finally obtained after polishing.

As described above, the copper plating device 620 having the filmthickness distribution adjusting function is used, and feedbackcontrolled to deposit a plated copper film more uniformly on the surfaceof the substrate. Furthermore, the CMP device 624 having the polishingamount adjusting function is used, and the amount of polishing of theplated copper film is adjusted based on the actual measurements of thefilm thickness distribution, whereby a flat plated copper film can beobtained finally.

As shown in FIG. 27, the film thickness distributions over the entiresurface at the center and the periphery of the plated copper film afterpolishing with the CMP device 624 may be measured with a film thicknessdistribution measuring device 626, and based on the results of thesemeasurements, the CMP device 624 may be feedback controlled (for fineadjustment of the pressure against the substrate).

FIGS. 28 to 40 show different examples of the copper plating device 620having the film thickness distribution adjusting mechanism. Membersidentical with or corresponding to the members of the conventionalexample shown in FIG. 64 will be assigned the same numerals, and theirexplanation will be omitted partially.

FIG. 28 shows a copper plating device 620 which includes a flatplate-shaped, high resistance structure (virtual anode) 630 disposedbetween an anode plate (anode) 606 immersed in a plating liquid 600 in aplating tank 602, and a substrate W held by a substrate holder 604 anddisposed in an upper part of the plating tank 602. The high resistancestructure 630 has higher electrical resistivity than that of the platingliquid 600, and comprises, for example, a film or a ceramic plate. Thehigh resistance structure 630 is placed parallel to the anode plate 606over the entire region of a cross section of the plating tank 602.

According to this arrangement, the electric resistance between the anodeplate 606 and the copper seed layer 7 (see FIG. 62A) formed on thesurface (lower surface) of the substrate W can be made higher via thehigh resistance structure 630 than the electric resistance produced whenthe gap between them consists of the copper plating liquid 600 alone.This can diminish the difference in electric current density over theentire surface due to the influence of the electric resistance of thecopper seed layer 7 formed on the surface of the substrate W.Consequently, the influence of the electric resistance of the copperseed layer can be decreased, without fully lengthening the distancebetween the anode plate 606 and the substrate W, so that the filmthickness of the plated copper film can be rendered more uniform.

FIG. 29 shows a copper plating device 620 which includes a flatplate-shaped insulator (virtual anode) 632 placed between an anode plate606 and a substrate W parallel to them instead of the high resistancestructure 630 in FIG. 28. The insulator 632 has a central hole 632 a atthe center, and is a size smaller than the cross section of a platingtank 602. Because of this insulator 632, a plating electric currentflows only through the interior of the central hole 632 a of theinsulator 632 and through the gaps between the outer peripheral endsurface of the insulator 632 and the inner circumferential surface ofthe plating tank 602, thereby thickening a plated copper film deposited,particularly, at the center of the substrate W.

FIG. 30 shows a copper plating device 620 which includes the insulator632 of FIG. 29 having a larger size, and having an outer peripheral endsurface brought into contact with the inner circumferential surface ofthe plating tank 602. Because of this configuration, a plating electriccurrent flows only through the interior of the central hole 632 a of theinsulator 632, thereby further thickening a plated copper film depositedat the center of the substrate W.

FIG. 31 shows a copper plating device 620 which includes a conductor(virtual anode) 634 placed between an anode plate 606 and a substrate Wat a position corresponding to the center of the substrate W. Theconductor 634 has lower electric resistivity than that of a platingliquid 600. More plating electric current flows through the conductor634, thereby making a thicker plated copper film deposited at the centerof the substrate W.

FIG. 32 is a modification of FIG. 29, showing a copper plating device620 which includes an insulator 632 having a plurality of through-holes632 b of an arbitrary size (internal diameter) at arbitrary positionsthereof. Because of this configuration, a plating electric current flowsonly through the interior of the through-holes 632 b, thereby makinglarger the film thickness of a plated copper film at the arbitrarypositions of the substrate W.

FIG. 33 is a modification of FIG. 32, showing a copper plating device620 which includes insulator having a plurality of through-holes 632 bof an arbitrary size at arbitrary positions thereof, and a conductor 636buried in the arbitrary through-hole 632 b. According to thisconfiguration, a greater plating electric current flows through theinterior of the conductor 636 than through the interior of theconductor-free through-holes 632 b, thereby depositing a copper film ofa larger thickness at the arbitrary position of the substrate W.

FIG. 34 shows a modification of FIG. 28, showing a copper plating device620 which includes a high resistance structure 630 having higherelectric resistivity than that of the plating liquid 600 and comprising,for example, a film or a ceramic plate. The high resistance structure630 has a thickness gradually increasing, beginning at the center,toward the periphery. The electric resistance of the high resistancestructure 630 is higher on the periphery than at the center, thus makingthe influence of the electric resistance of the copper seed layersmaller. As a result, a plated copper film with a more uniform thicknessis deposited on the surface of the substrate W.

FIG. 35 shows a modification of FIG. 32, showing a copper plating device620 which includes an insulator 632 having a plurality of through-holes632 c of the same size (internal diameter) at arbitrary positionsthereof to distribute the through-holes 632 c of the same sizearbitrarily over the plane of the substrate W. By so doing, theinsulator 632 can be made easily.

FIG. 36 shows a copper plating device 620 which includes an anode plate606 bulges upward like a mountain at the center compared with theperipheral edge. Thus, the distance of the center of the anode plate 606from the substrate W is shorter than the distance of the periphery ofthe anode plate 606 from the substrate W. As a result, a greater platingelectric current than in a normal situation flows through the center ofthe substrate, thereby depositing a plated copper film of a uniformthickness on the substrate.

FIG. 37 shows a modification of FIG. 36, showing a copper plating device630 which includes a flat plate-shaped anode plate 606 curved upward inthe form of a spherical crust, whereby the distance of the center of theanode plate 606 from the substrate W is shorter than the distance of theperiphery of the anode plate 606 from the substrate W.

A so-called black film is formed on the surface of the anode plate(anode) 606. If a peeled piece of the black film approaches and adheresto the treated surface (surface) of the substrate W, it adverselyaffects the plated copper film. Thus, it is preferred to surround theanode plate 606 with a filter film 638, as shown in FIG. 38, and preventthe outflow of the peeled piece of the black film by use of the filterfilm 638. In this example, provision of the filter film 636 is appliedto the example shown in FIG. 30, but needless to say, can be similarlyapplied to other examples.

FIG. 39 shows a copper plating device 630 which includes the sameinsulator 632 having the central hole 632 a shown in FIG. 29. Thisinsulator 632 is connected to an upwardly and downwardly moving rod 642of an upwardly and downwardly moving mechanism 640, and the relativeposition of the insulator 632 relative to the positive electrode 606 andthe substrate W is changed in accordance with driving of the upwardlyand downwardly moving mechanism 640. According to this contrivance, theelectric field between the anode plate 606 and the substrate W can beadjusted via the insulator 632.

FIG. 40 shows a copper plating device 630 which includes a disk-shapedinsulator (virtual anode) 644 having a plurality of through-holes 644 a,and a similarly disk-shaped insulator (virtual anode) 646 having aplurality of through-holes 646 a and stacked rotatably on the insulator644. One of the insulators 646, is rotated via a rotating rod 650 of arotating mechanism 648 to change the phases of both insulators 644 and646. The number of the through-holes 644 a and 646 a of the insulators644 and 646 communicating with each other is changed in accordance withthe change in the phases. According to this design, the electric fieldbetween the anode plate 606 and the substrate W can be adjusted byadjusting the angle of rotation of the insulator 646.

FIGS. 41 to 46 show the CMP device (polishing device) 624 having apolishing amount adjusting mechanism.

FIGS. 41 and 42 show a CMP device 624 which includes a polishing belt652 composed of belt-shaped polishing cloth or a cloth having abrasivegrains fixed thereto. The polishing belt 652 is looped between a pair ofrollers 654 and 654, with its polishing surface directed outward. Asubstrate W attracted and held by a polishing head 656 is pressedagainst the polishing belt 652 which is traveling, with the substrate Wbeing rotated. The polishing surface of the polishing belt 652 issupplied with an abrasive liquid or pure water (containing a pHadjustor) from an abrasive liquid supply nozzle 658.

A press device 668 is disposed below the polishing head 656 and at aposition at which the press device 668 and the polishing head 656sandwich the polishing belt 652 running upper side. The press device 668comprises a central disk 664 and an annular plate 666 surrounding thecentral disk 664. The central disk 664 and the annular plate 666 arehoused in a housing 660 and can be raised and lowered individually viaactuators 662 a, 662 b. Because of this press device 668, the uppersurface of the annular plate 666, for example, can be caused to protrudeabove the upper surface of the central disk 664, thereby making itpossible to make the amount of polishing of the peripheral edge portionof the substrate W larger than that of the central portion of thesubstrate W.

In this case, the polishing head 656 may be one exerting a singlepressure on the entire surface of the substrate, or may be a top ring300 as shown in FIGS. 9 to 16.

As shown in FIGS. 43A and 43B, Teflon 670 (trademark) may be bonded tothe upper surfaces of the central disk 664 and the annular plate 666,whereby friction occurring between the polishing belt 652 and thecentral disk 664, and the polishing belt 652 and the annular plate 666can be diminished.

In polishing copper, the use of abrasive grains fixed to the belt ispreferred to the use of the polishing cloth as the polishing surfacesupplied with an abrasive liquid, because dishing can be minimized forcopper which is a soft metal.

FIGS. 44 to 46 show another example of the CMP device 624. In the CMPdevice 624, a rotary table 676 of a larger diameter than that of asubstrate W is coupled to the upper end of a rotating shaft 674 whichrotates in accordance with the rotation of a motor 672. The substrate Wis held to the upper surface of the rotary table 676, with itsdevice-formed face (surface) directed upward, and is rotated in thisstate. A polishing tool 678 having abrasive grains or an abrasive clothfixed thereto and having a diameter smaller than the radius of thesubstrate W is pressed, while being rotated, against the substrate W,and simultaneously an abrasive liquid or pure water is supplied from anabrasive liquid supply nozzle 680 to the surface of the substrate W topolish the substrate W. The film thickness of the plated copper filmafter polished is measured by a film thickness sensor 682 at theposition located beside the polishing tool 678.

The polishing tool 678 is moved in the diametrical direction of thesubstrate to perform polishing of the entire surface of the substrate.If the plated copper film is thicker on the periphery of the substratethan at the center of the substrate, the radially moving speed of thepolishing tool 678 on the periphery of the substrate should be slowed.Moreover, the film thickness sensor 682, such as an optical sensor, ismounted in order to control the radially moving speed of the polishingtool 678 while measuring the plated copper film thickness at the annularzone of the substrate being polished. By so doing, the plated copperfilm of a film thickness different between the center and periphery ofthe substrate can be flattened. In this case, as shown in FIG. 46, theposition of the film thickness sensor 682 is preferably downstream fromthe polishing tool 678 in the rotating direction of the substrate, andposition of the supply of the abrasive liquid is desirably upstream fromthe polishing tool 678 in the rotating direction of the substrate.

Some or all of the copper plating device 620 having the film thicknessadjusting mechanism for the plated copper film at the center and theperiphery of the substrate W, the film thickness distribution measuringdevice 622, and the CMP device (polishing device) 624 capable ofadjusting the amount of polishing at the center and the periphery of thesubstrate W may be integrated into a single apparatus.

The following embodiments show examples of the integrated apparatus. Aseed layer forming chamber may be added to an integrated apparatus asshown in FIG. 47. Formation of the seed layer can be performed using anordinary CVD device or sputtering device, or by electroless-plating. Abarrier layer forming device may be included in the integral type.

FIG. 47 is a view showing a plan configuration of a semiconductorsubstrate processing apparatus. The present semiconductor substrateprocessing apparatus comprises a loading/unloading portion 701, a copperplating device 620, a first robot 703, a third cleaner 704, an invertingmachine 705, an inverting machine 706, a second cleaner 707, a secondrobot 708, a first cleaner 709, a first CMP device 624 a, and a secondCMP device 624 b. A film thickness distribution measuring device 622 formeasuring the film thicknesses of the plated film before and afterplating, and a film thickness distribution measuring device 626 formeasuring the film thickness of the dry plated copper film on thesemiconductor substrate W after polishing are disposed near the firstrobot 703.

The film thickness distribution measuring devices 622, 626, especially,the film thickness distribution measuring device 626 for measuring thefilm thickness distribution after polishing, may be provided on the handof the first robot 703. The film thickness distribution measuring device622, although not illustrated, may be provided at the semiconductorsubstrate carry-in/carry-out port of the copper plating device 620 tomeasure the film thickness of the semiconductor substrate W carried in,and the film thickness of the semiconductor substrate W carried out.

The first CMP device 624 a comprises a polishing table 710 a, a top ring710 b, a top ring head 710 c, a film thickness distribution measuringdevice 626 a, and a pusher 710 e. The second CMP device 624 b comprisesa polishing table 711 a, a top ring 711 b, a top ring head 711 c, a filmthickness distribution measuring device 626 b, and a pusher 711 e.

A box housing a substrate cassette 22 accommodating semiconductorsubstrates W having a contact hole 3 and a trench 4 for aninterconnection, and a seed layer 7 formed thereon is placed on thestage of the loading/unloading portion 701. The box is opened by a boxopening/closing mechanism, and then the semiconductor substrate W iswithdrawn from the substrate cassette 22 by the first robot 703, andcarried into the copper plating device 620 for forming a copper film 6.Before formation of the copper film 6, the film thickness of the seedlayer 7 is measured with the film thickness distribution measuringdevice 626. Formation of the copper film 6 is carried out by copperplating device 620. After formation of the copper film 6, the substrateis rinsed or cleaned by the copper plating device 620. If time permits,the substrate may be dried.

When the semiconductor substrate W is withdrawn from the copper platingdevice 620 by the first robot 703, the film thickness distribution ofthe copper film (plated copper film) 6 is measured with the filmthickness distribution measuring device 626. The measuring method is thesame as for the seed layer 7. The results of the measurement arerecorded in a recorder (not shown) as recorded data on the semiconductorsubstrate, and are also used for judgement of an abnormality of thecopper plating device 620. After the film thickness is measured, thefirst robot 703 transfers the semiconductor substrate W to the invertingmachine 705, which turns the semiconductor substrate W upside down (thesurface where the copper film 6 has been formed is directed downward).

The second robot 708 picks up the semiconductor substrate W on theinverting machine 705, and places the semiconductor substrate W on thepusher 710 e of the CMP device 624 a. The top ring 710 b attracts thesemiconductor substrate W on the pusher 710 e, and presses the surface,where the copper film 6 has been formed, of the semiconductor substrateW against the polishing surface of the polishing table 710 a to carryout polishing.

Silica, alumina or ceria is used as abrasive grains for polishing of thecopper film 6, and a material for oxidizing copper mainly with an acidicmaterial, such as hydrogen peroxide, is used as an oxidizing agent. Anadjusted temperature fluid piping for passing a liquid adjusted to apredetermined temperature is connected to the interior of the polishingtable 710 a in order to maintain the temperature of the polishing table710 a at a predetermined value. In order that the temperature of aslurry containing the abrasive grains and oxidizing agent is alsomaintained at a predetermined value, a temperature adjustor is providedin a slurry nozzle for ejecting the slurry. The temperature of water orthe like for dressing is also adjusted, although this is not shown. Inthis manner, the temperature of the polishing table 710 a, thetemperature of the slurry, and the temperature of water or the like fordressing are kept at predetermined values, whereby the chemical reactionrate is kept constant. As the polishing table 710 a, in particular,alumina or ceramic, such as SiC, with high thermal conductivity is used.

To detect the end point of polishing, there is performed film thicknessmeasurement of the copper film 6 by use of an eddy current type filmthickness measuring machine or an optical film thickness measuringmachine provided on the polishing table 710 a; or surface detection ofthe barrier layer 5. The time when the film thickness of the copper film6 is found to be zero or when the surface of the barrier layer 5 isdetected is taken as the end point of polishing.

After polishing of the copper film 6 is completed, the top ring 710 breturns the semiconductor substrate W onto the pusher 710 e. The secondrobot 708 takes up the semiconductor substrate W, and puts it into thefirst cleaner 709. At this time, a chemical liquid may be jetted at theface side and back side of the semiconductor substrate Won the pusher710 e to remove particles or make particles difficult to adhere.

In the first cleaner 709, the face side and back side of thesemiconductor substrate W are scrub cleaned with, for example, a PVAsponge roll. In the first cleaner 709, cleaning fluid ejected from thenozzle is mainly pure water, but may be one mixed with a surfactantand/or a chelating agent, and then pH adjusted in harmony with the zetapotential of copper oxide. Also, an ultrasonic vibratory element may beprovided on the nozzle to apply ultrasonic vibrations to the cleaningfluid ejected. During scrub cleaning, the semiconductor substrate W isgripped by a rotating roller and rotated in a horizontal plane.

After completion of cleaning, the second robot 708 transfers thesemiconductor substrate W to the second CMP device 624 b, and places thesemiconductor substrate Won the pusher 711 e. The top ring 711 battracts the semiconductor substrate W on the pusher 711 e, and pressesthe surface, where the barrier layer 5 has been formed, of thesemiconductor substrate W against the polishing surface of the polishingtable 711 a to carry out polishing. The configurations of the polishingtable 711 a and top ring 711 b are the same as those of the polishingtable 710 a and top ring 710 b.

The polishing surface on the top of the polishing table 711 a iscomposed of a polyurethane foam such as IC1000, or the one havingabrasive grains fixed thereto or impregnated with abrasive grains.Polishing is performed by the relative movement of the polishing surfaceand the semiconductor substrate W. At this time, silica, alumina orceria is used for abrasive grains or slurry. A chemical liquid isadjusted according to the type of the film to be polished.

After polishing is completed, the top ring 711 b transfers thesemiconductor substrate W to the pusher 711 e. The second robot 708takes up the semiconductor substrate W on the pusher 711 e. At thistime, a chemical liquid may be jetted at the face side and back side ofthe semiconductor substrate W on the pusher 711 e to remove particles ormake particles difficult to adhere.

The second robot 708 transfers the semiconductor substrate W to thesecond cleaner 707 for cleaning. The configuration of the second cleaner707 is also the same as the configuration of the first cleaner 709. Purewater is mainly used as a cleaning fluid for removal of particles, and asurfactant, a chelating agent, or a pH adjusting agent may be used. Thesurface of the semiconductor substrate W is scrub cleaned with a PVAsponge roll. A strong chemical liquid, such as DHF, is ejected from thenozzle toward the back side of the semiconductor substrate W to etchdiffused copper. Without the problem of diffusion, the back side of thesemiconductor substrate W is scrub cleaned with a PVA sponge roll usingthe same chemical liquid as for the surface of the semiconductorsubstrate W.

Upon completion of the above cleaning, the second robot 708 takes up thesemiconductor substrate W, and transfers it to the inverting machine706, which turns the semiconductor substrate W upside down. The thusinverted semiconductor substrate W is picked up by the first robot 703and placed in the third cleaner 704. The third cleaner 704 jetsmegasonic water, which has been excited by ultrasonic vibrations, at thesurface of the semiconductor substrate W to clean the semiconductorsubstrate W. At this time, pure water, a surfactant, a chelating agent,or a pH adjusted agent may be added, and the surface of thesemiconductor substrate W may be cleaned with a publicly known penciltype sponge. Then, the semiconductor substrate W is dried by spindrying.

FIG. 48 is a view showing the plan layout of another example of thesubstrate processing apparatus. This substrate processing apparatuscomprises a barrier layer forming unit 811, a seed layer forming unit812, a plating film forming unit (plating device) 813, an annealing unit814, a first cleaning unit 815, a bevel/back side cleaning unit 816, acap-plating unit 817, a second cleaning unit 818, a first aligner andfilm thickness measuring instrument 841, a second aligner and filmthickness measuring instrument 842, a first substrate inverting machine843, a second substrate inverting machine 844, a substrate temporaryplacing table 845, a third film thickness measuring instrument 846, aloading/unloading portion 820, a first CMP device 821, a second CMPdevice 822, a first robot 831, a second robot 832, a third robot 833,and a fourth robot 834.

In this example, an electroless copper plating device can be used as thebarrier layer forming unit 811, an electroless copper plating device canbe used as the seed layer forming unit 812, and an electric platingdevice can be used as the plating film forming unit 813.

FIGS. 49A to 49E show an example in which the film thicknessdistribution is adjusted more uniformly by two copper plating deviceshaving different film thickness distribution characteristics. As shownin FIG. 49B, the first-stage plating device 620 a is one designed todeposit a plated copper film P₁ having film thickness distributioncharacteristics with the film thickness increasing on the periphery. Asshown in FIG. 49C, the second-stage plating device 620 b is one designedto deposit a plated copper film P₂ having film thickness distributioncharacteristics with the film thickness increasing at the center.

These two copper plating devices 620 a and 620 b are arranged in seriesto perform copper plating of the substrate, thereby depositing theplated copper film P₁ as shown in FIG. 49D, and then depositing theplated copper film P₂ thereon as shown in FIG. 49E. By adjusting theperiods of time for these plating steps, a plated copper film with amore uniform film thickness distribution can be obtained. This methodcan change the thickness distribution at the center and periphery of thesubstrate even during plating. Since the method needs only changes inthe plating time and does not require a mechanical adjusting mechanism,it can adjust the plated copper film thickness distribution in situ.

If the film thickness of the plated copper film after the second-stageplating is larger at the center, an adjustment is made to increase theplating time or the plating electric current for the first-stageplating, or to decrease the plating time or the plating electric currentfor the second-stage plating. This adjustment makes it possible todecrease variations in the film thickness of the plated copper film atthe center and periphery of the substrate after the second-stageplating.

It goes without saying that the first-stage plating device may be onedesigned to deposit a plated copper film having film thicknessdistribution characteristics with the film thickness increasing at thecenter, and the second-stage plating device may be one designed todeposit a plated copper film having film thickness distributioncharacteristics with the film thickness increasing on the periphery.

As shown in FIG. 50, it is acceptable to perform the first-stage platingby the first-stage plating device 620 a, measure the film thicknessdistribution of the plated copper film by a film thickness distributionmeasuring device 622 a, and adjust the plating period of thesecond-stage plating device 620 b on the basis of the results ofmeasurement. In this case, it is possible to further decrease variationsin the film thickness of the plated copper film at the center andperiphery of the substrate after the second-stage plating.

In this manner, the combined use of the plating device capable ofadjusting the film thickness of the plated copper film at the center andperiphery of the substrate, and the film thickness distributionmeasuring device for the center and periphery of the substrate enablesan adjustment to be made so as to decrease variations in the filmthickness of the plated copper film at the center and periphery of thesubstrate after plating. This can be achieved by a simple adjustment, aswell as automation by a control device using common techniques such asfeedback control and/or feed forward control. Furthermore, it ispossible not only to make an adjustment so as to decrease variations inthe film thickness of the plated copper film at the center and peripheryof the substrate, but also to plate a plated copper film having adistribution of the film thickness of the plated copper film at thecenter and periphery of the substrate, the distribution adapted to thepolishing properties of a CMP device for the periphery and center of thesubstrate. For example, when the plating device is combined with apolishing device which polishes more at the center than on the peripheryof the substrate, it is recommendable to plate a plated copper filmthicker at the center than on the periphery of the substrate.

To polish the plated copper film, the CMP device used here, which canadjust the pressures on the center and the periphery of the substrateindependently, may be an ordinary CMP device which presses a substrateheld by a rotating head against a polishing cloth attached to anordinary rotary table, and polishes the substrate with an abrasiveliquid supplied to the polishing cloth. However, a fixed abrasive graintype polishing device having abrasive grains fixed thereto is desired inorder to prevent dishing. The desired head is one which presses thesubstrate by a fluid pressure. When the fixed abrasive grain typepolishing device is used, scratches due to polishing may occur on thesurface of the plated copper film. To remove them, it is desirable topolish the substrate with the fixed abrasive grains at the first stage,and carry out ordinary polishing with a polishing cloth and an abrasiveliquid at the second stage, thereby removing the scratches.

The plating device having the film thickness distribution adjustingmechanism for the plated copper film at the center and periphery of thesubstrate, the film thickness distribution measuring device, and the CMPdevice capable of adjusting the polishing amount for the center andperiphery of the substrate may be housed separately in the clean room.In this case, in order to prevent oxidation of the surface of the platedcopper film, it is desirable to use the substrate transport box such asSMIF or HOOP mentioned in the previous embodiments, and further use atransport device adapted to circulate gases inside the substratetransport box, and isolate the gases in the atmosphere around thesubstrate from the clean room by a particle filter placed inside thesubstrate transport box, or this particle filter combined with achemical filter and further a dehumidifier, thereby controlling theamount of particles, the amount of oxygen, or the amount of steam.Moreover, the atmosphere inside each device is desirably isolated fromthe clean room by a partition or the like, with the amount of oxygen orsteam inside the device being controlled.

Further, as shown in FIG. 51, the electric resistance of the copper seedlayer 7 formed on the surface of the substrate may be measured beforecopper plating, and based on the results, the film thicknessdistribution adjusting mechanism of the copper plating device for thecenter and periphery of the plated copper film may be adjusted. Thismeasurement of the electric resistance of the copper seed layer may bemade using a device other than the plating device. However, it isdesired to measure the resistance between the cathode and the copperseed layer in the actual plating state, so that the electric resistanceof the copper seed layer should be measured using the cathode contactsof the plating device.

FIGS. 52 to 63 show examples of an electric terminal members servingconcurrently as copper seed layer resistance measuring terminals and acathode. As shown in FIGS. 52 and 53, a semiconductor substrate W isplaced on a substrate placing stand 900 composed of an isolator, withthe copper seed layer formed surface of the substrate being directeddownward. On a surface of the substrate placing stand 900 receiving thesubstrate W, a plurality of electric terminals 902 are arranged with apredetermined pitch along the circumferential direction. Whenconcurrently used as a cathode, the electric terminals 902, at least,need to be prevented from contacting with a plating liquid. For thispurpose, sealing members 904, 906 are arranged on both sides (outsideand inside) of the electric terminals 902, and the sealing member 609 ispressed by a seal press 908, whereby a sealing mechanism is constitutedin this example. Only the inner sealing material 906 for the electricterminal 902 may be provided.

The electric terminal 902 is formed in a rectangular shape in thisembodiment, but may be in the form of a knife edge making linear contactwith the copper seed layer, as shown in FIG. 54A. Also, the electricterminal 902 may be pinnacle-shaped so as to make point contact with thecopper seed layer, although this is not shown. The point contact candecrease electric resistance between the electric terminal and thecopper seed layer.

As shown in FIG. 54B, moreover, it is desired to provide a structure inwhich a spring 910 is disposed beneath each electric terminal 902,whereby each electric terminal 902 is urged upward by the elastic forceof the spring 910 and independently pressed against the copper seedlayer with a constant force. In addition, as shown in FIG. 54C, theremay be a structure in which the electric terminal 902 is composed of abent metallic plate and can be pressed, by itself, against the copperseed layer. At least the surface of the electric terminal 902 isdesirably made of metal or platinum in order to decrease contactresistance between the electric terminal and the copper seed layer.

The substrate placing stand 900 desirably has a centering mechanism inorder that the electric terminal 902 does not disengage from thesubstrate W. Examples of the centering structure are one in which aninner circumferential surface of the substrate placing stand 900 broughtin contact with the substrate W is a tapered surface 900 a, as shown inFIG. 55A, and one in which a metal plate is bent so as to have acentering mechanism for the substrate, thereby constituting an electricterminal 902, and a centering mechanism for the substrate is imparted tothe electric terminal 902 itself, as shown in FIG. 55B.

In these examples, the device for measuring the resistance of the copperseed layer measures the resistance, with the copper seed layer facingdownward. Needless to say, however, the resistance may be measured, withthe copper seed layer facing upward.

Next, the method of measuring the electric resistance of the copper seedlayer will be described.

To measure the resistance of the copper seed layer, it is recommendableto apply a direct current voltage between the two electric terminals 902and 902 located opposite to each other with respect to the center of thesubstrate W, and measure an electric current flowing between the twoelectric terminals 902 and 902. By performing this measurement betweenthe electric terminals 902 and 902 sandwiching the enter of thesubstrate W, as shown in FIG. 56, a plurality of data (four data in thisexample, because eight of the electric terminals are present) can beobtained. Since errors exist in the measurements of electric resistance,the resistance value of the entire substrate can be found by variousmethods, such as calculating the arithmetic mean of the data,calculating the root mean square, and averaging the measured data withthe exception of the maximum value and the minimum value.

The thus obtained measured value of the electric resistance of the seedlayer is compared with the standard value of the electric resistance ofthe seed layer. If the measured value is greater than the standardvalue, there is a possibility that the plated copper film will bethicker on the periphery of the substrate than at the center of thesubstrate. Thus, the substrate center/periphery film thickness adjustingmechanism of the copper plating device is adjusted so that the platedcopper film will be flat.

Furthermore, as shown in FIG. 57, two adjacent electric terminals 902and 902 may be used as one electrode to measure resistance between thesetwo adjacent electric terminals and the corresponding two adjacentelectric terminals located on the opposite side relative to the centerof the substrate. In this case, as shown in FIGS. 58A and 58B,combinations of the electric terminals 902 may be changed sequentiallyusing the adjacent electric terminals 902 to make measurements.

In addition, as shown in FIGS. 59A to 59C, the electric resistancesbetween the arbitrary electric terminals 902 and 902 arranged around theedge of the substrate W may be measured (for example, the number of theelectric terminals in this example is eight, so that there are at most720 measurements), and the corresponding simultaneous equations may besolved, whereby the planar distribution of the electric resistance ofthe copper seed layer can be approximatively obtained. The use of thismethod approximatively gives the electric resistances R₁₀ to R₈₀ betweenthe center of the substrate and the surroundings of the substrate edgeas shown in FIG. 61.

FIGS. 60 and 61 show other example of measuring the distribution of theelectric resistance of the copper seed layer. This example includes anelectrode terminal arm 914 having a central electric terminal 912,brought into contact with the copper seed layer at the center of thesubstrate W. In this example, the electrode terminal arm 914 is of amovable type, and moves to the center of the substrate w only whenmeasuring the electric resistance, and retreats when plating isperformed.

In this example, a direct current voltage is sequentially appliedbetween the central electric terminal 912 at the center of the substrateand the respective electric terminals 902 arranged around the edge ofthe substrate. The values of electric current flowing at this time aremeasured, thereby making it possible to find the electric resistancesR₁₀, R₂₀ . . . R₈₀ of the copper seed layer between the central electricterminal 912 disposed at the center of the substrate and the respectiveelectric terminals 902 arranged around the edge of the substrate asshown in FIG. 61.

Based on the thus found electric resistance distribution (e.g., R₁₀ toR₈₀) of the copper seed layer, voltages to be applied to the respectiveelectric terminals of the cathode at the time of copper plating areadjusted and controlled independently, thus making it possible to adjustnot only the distribution of the film thickness of the plated copperfilm in the radial direction of the substrate, but also the distributionof the film thickness of the plated copper film in the circumferentialdirection of the substrate. These adjustments may be made automaticallyby use of an ordinary control device adopting feed forward sequencecontrol.

FIG. 65 is a plan view of an example of a substrate plating apparatus.The substrate plating apparatus shown in FIG. 65 comprises aloading/unloading area 1520 for housing substrate cassettes whichaccommodate semiconductor substrates, a processing area 1530 forprocessing semiconductor substrates, and a cleaning/drying area 1540 forcleaning/drying plated semiconductor substrates. The cleaning/dryingarea 1540 is positioned between the loading/unloading area 1520, and theprocessing area 1530. A partition 1521 is disposed between theloading/unloading area 1520, and the cleaning/drying area 1540. And apartition 1523 is disposed between the cleaning/drying area 1540, andthe processing area 1530.

The partition 1521 has a passage (not shown) defined therein fortransferring semiconductor substrates therethrough between theloading/unloading area 1520, and the cleaning/drying area 1540, andsupports a shutter 1522 for opening/closing the passage. The partition1523 has a passage (not shown) defined therein for transferringsemiconductor substrates therethrough between the cleaning/drying area1540, and the processing area 1530, and supports a shutter 1524 foropening/closing the passage. The cleaning/drying area 1540 and theprocessing area 1530 can independently be supplied with and dischargeair.

The substrate plating apparatus shown in FIG. 65 is placed in a cleanroom, which accommodates semiconductor fabrication facilities. Thepressures in the loading/unloading area 1520, the processing area 1530,and the cleaning/drying area 1540 are selected as follows:

The pressure in the loading/unloading area 1520>the pressure in thecleaning/drying area 1540>the pressure in the processing area 1530.

The pressure in the loading/unloading area 1520 is lower than thepressure in the clean room. Therefore, air does not flow from theprocessing area 1530 into the cleaning/drying area 1540, and air doesnot flow from the cleaning/drying area 1540 into the loading/unloadingarea 1520. Furthermore, air does not flow from the loading/unloadingarea 1520 into the clean room.

The loading/unloading area 1520 houses a loading unit 1520 a and anunloading unit 1520 b, each accommodating a substrate cassette forstoring semiconductor substrates. The cleaning/drying area 1540 housestwo water cleaning units 1541 for cleaning plated semiconductorsubstrates with water, and two drying units 1542 for drying platedsemiconductor substrates. Each of the water cleaning units 1541 maycomprise a pencil-shaped cleaner with a sponge layer mounted on a frontend thereof or a roller with a sponge layer mounted on an outercircumferential surface thereof. Each of the drying units 1542 maycomprise a drier for spinning a semiconductor substrate at a high speedto dehydrate and dry. The cleaning/drying area 1540 also has a transferunit (transfer robot) 1543 for transferring semiconductor substrates.

The processing area 1530 houses a plurality of pretreatment chambers1531 for pretreating semiconductor substrates prior to being plated, anda plurality of plating chambers 1532 for plating semiconductorsubstrates with copper. The processing area 1530 also has a transferunit (transfer robot) 1543 for transferring semiconductor substrates.

FIG. 66 shows in side elevation air flows in the substrate platingapparatus. As shown in FIG. 66, fresh air is introduced from theexterior through a duct 1546 and forced through high-performance filters1544 by fans from a ceiling 1540 a into the cleaning/drying area 1540 asdownward clean air flows around the water cleaning units 1541 and thedrying units 1542. Most of the supplied clean air is returned from afloor 1540 b through a circulation duct 1545 to the ceiling 1540 a, fromwhich the clean air is forced again through the filters 1544 by the fansinto the cleaning/drying area 1540. Part of the clean air is dischargedfrom the wafer cleaning units 1541 and the drying units 1542 through aduct 1552 out of the cleaning/drying area 1540.

In the processing area 1530 which accommodates the pretreatment chambers1531 and the plating chambers 1532, particles are not allowed to beapplied to the surfaces of semiconductor substrates even though theprocessing area 1530 is a wet zone. To prevent particles from beingapplied to semiconductor substrates, downward clean air flows around thepretreatment chambers 1531 and the plating chambers 1532. Fresh air isintroduced from the exterior through a duct 1539 and forced throughhigh-performance filters 1533 by fans from a ceiling 1530 a into theprocessing area 1530.

If the entire amount of clean air as downward clean air flows introducedinto the processing area 1530 were always supplied from the exterior,then a large amount of air would be required to be introduced into anddischarged from the processing area 1530 at all times. According to thisembodiment, air is discharged from the processing area 1530 through aduct 1553 at a rate sufficient enough to keep the pressure in theprocessing area 530 lower than the pressure in the cleaning/drying area1540, and most of the downward clean air introduced into the processingarea 1530 is circulated through circulation ducts 1534, 1535. Thecirculation duct 1534 extends from the cleaning/drying area 1540 and isconnected to the filters 1533 over the ceiling 1530 a. The circulationduct 1535 is disposed in the cleaning/drying area 1540 and connected tothe pipe 1534 in the cleaning/drying area 1540.

The circulating air that has passed through the processing area 1530contains a chemical mist and gases from solution bathes. The chemicalmist and gases are removed from the circulating air by a scrubber 1536and mist separators 1537, 1538 which are disposed in the pipe 1534 thatis connected to the pipe 1535. The air which circulates from thecleaning/drying area 1540 through the scrubber 1536 and the mistseparators 1537, 1538 back into the circulation duct 1534 over theceiling 1530 a is free of any chemical mist and gases. The clean air isthen forced through the filters 1533 by the fans to circulate back intothe processing area 1530.

Part of the air is discharged from the processing area 1530 through theduct 1553 connected to a floor 1530 b of the processing area 1530. Aircontaining a chemical mist and gases is also discharged from theprocessing area 1530, through the duct 1553. An amount of fresh airwhich is commensurate with the amount of air discharged through the duct1553 is supplied from the duct 1539 into the plating chamber 1530 underthe negative pressure developed therein with respect to the pressure inthe clean room.

As described above, the pressure in the loading/unloading area 1520 ishigher than the pressure in the cleaning/drying area 1540 which ishigher than the pressure in the processing area 1530. When the shutters1522, 1524 (see FIG. 65) are opened, therefore, air flows successivelythrough the loading/unloading area 1520, the cleaning/drying area 1540,and the processing area 1530, as shown in FIG. 67. Air discharged fromthe cleaning/drying area 1540 and the processing area 1530 flows throughthe ducts 1552, 1553 into a common duct 1554 (see FIG. 68) which extendsout of the clean room.

FIG. 68 shows in perspective the substrate plating apparatus shown inFIG. 65, which is placed in the clean room. The loading/unloading area1520 includes a side wall which has a cassette transfer port 1555defined therein and a control panel 1556, and which is exposed to aworking zone 1558 that is compartmented in the clean room by a partitionwall 1557. The partition wall 1557 also compartments a utility zone 1559in the clean room in which the substrate plating apparatus is installed.Other sidewalls of the substrate plating apparatus are exposed to theutility zone 1559 whose air cleanness is lower than the air cleanness inthe working zone 1558.

As described above, the cleaning/drying area 1540 is disposed betweenthe loading/unloading area 1520, and the processing area 1530. Thepartition 1521 is disposed between the loading/unloading area 1520, andthe cleaning/drying area 1540. The partition 1523 is disposed betweenthe cleaning/drying area 1540, and the processing area 1530. A drysemiconductor substrate is loaded from the working zone 1558 through thecassette transfer port 1555 into the substrate plating apparatus, andthen plated in the substrate plating apparatus. The plated semiconductorsubstrate is cleaned and dried, and then unloaded from the substrateplating apparatus through the cassette transfer port 1555 into theworking zone 1558. Consequently, no particles and mist are applied tothe surface of the semiconductor substrate, and the working zone 1558which has higher air cleanness than the utility zone 1557 is preventedfrom being contaminated by particles, chemical mists, and cleaningsolution mists.

In the embodiment shown in FIGS. 65 and 66, the substrate platingapparatus has the loading/unloading area 1520, the cleaning/drying area1540, and the processing area 1530. However, an area accommodating achemical mechanical polishing unit may be disposed in or adjacent to theprocessing area 1530, and the cleaning/drying area 1540 may be disposedin the processing area 1530 or between the area accommodating thechemical mechanical polishing unit and the loading/unloading area 1520.Any of various other suitable area and unit layouts may be employedinsofar as a dry semiconductor substrate can be loaded into thesubstrate plating apparatus, and a plated semiconductor substrate can becleaned and dried, and thereafter unloaded from the substrate platingapparatus.

In the embodiment described above, the present invention is applied tothe substrate plating apparatus for plating a semiconductor substrate.However, the principles of the present invention are also applicable toa substrate plating apparatus for plating a substrate other than asemiconductor substrate. Furthermore, a region on a substrate plated bythe substrate plating apparatus is not limited to an interconnectionregion on the substrate. The substrate plating apparatus may be used toplate substrates with a metal other than copper.

FIG. 69 is a plan view of another example of a substrate platingapparatus. The substrate plating apparatus shown in FIG. 69 comprises aloading unit 1601 for loading a semiconductor substrate, a copperplating chamber 1602 for plating a semiconductor substrate with copper,a pair of water cleaning chambers 1603, 1604 for cleaning asemiconductor substrate with water, a chemical mechanical polishing unit1605 for chemically and mechanically polishing a semiconductorsubstrate, a pair of water cleaning chambers 1606, 1607 for cleaning asemiconductor substrate with water, a drying chamber 1608 for drying asemiconductor substrate, and an unloading unit 1609 for unloading asemiconductor substrate with an interconnection film thereon. Thesubstrate plating apparatus also has a wafer transfer mechanism (notshown) for transferring semiconductor substrates to the chambers 1602,1603, 1604, the chemical mechanical polishing unit 1605, the chambers1606, 1607, 1608, and the unloading unit 1609. The loading unit 1601,the chambers 1602, 1603, 1604, the chemical mechanical polishing unit1605, the chambers 1606, 1607, 1608, and the unloading unit 1609 arecombined into a single unitary arrangement as apparatus.

The substrate plating apparatus operates as follows: The wafer transfermechanism transfers a semiconductor substrate W on which aninterconnection film has not yet been formed from a substrate cassette1601-1 placed in the loading unit 1601 to the copper plating chamber1602. In the copper plating chamber 1602, a plated copper film is formedon a surface of the semiconductor substrate W having an interconnectionregion composed of an interconnection trench and an interconnection hole(contact hole).

After the plated copper film is formed on the semiconductor substrate Win the copper plating chamber 1602, the semiconductor substrate W istransferred to one of the water cleaning chambers 1603, 1604 by thewafer transfer mechanism and cleaned by water in one of the watercleaning chambers 1603, 1604. The cleaned semiconductor substrate W istransferred to the chemical mechanical polishing unit 1605 by the wafertransfer mechanism. The chemical mechanical polishing unit 1605 removesthe unwanted plated copper film from the surface of the semiconductorsubstrate W, leaving a portion of the plated copper film in theinterconnection trench and the interconnection hole. A barrier layermade of TiN or the like is formed on the surface of the semiconductorsubstrate W, including the inner surfaces of the interconnection trenchand the interconnection hole, before the plated copper film isdeposited.

Then, the semiconductor substrate W with the remaining plated copperfilm is transferred to one of the water cleaning chambers 1606, 1607 bythe wafer transfer mechanism and cleaned by water in one of the watercleaning chambers 1607, 1608. The cleaned semiconductor substrate W isthen dried in the drying chamber 1608, after which the driedsemiconductor substrate W with the remaining plated copper film servingas an interconnection film is placed into a substrate cassette 1609-1 inthe unloading unit 1609.

FIG. 70 shows a plan view of still another example of a substrateplating apparatus. The substrate plating apparatus shown in FIG. 70differs from the substrate plating apparatus shown in FIG. 69 in that itadditionally includes a copper plating chamber 1602, a water cleaningchamber 1610, a pretreatment chamber 1611, a protective layer platingchamber 1612 for forming a protective plated layer on a plated copperfilm on a semiconductor substrate, water cleaning chamber 1613, 1614,and a chemical mechanical polishing unit 615. The loading unit 1601, thechambers 1602, 1602, 1603, 1604, 1614, the chemical mechanical polishingunit 1605, 1615, the chambers 1606, 1607, 1608, 1610, 1611, 1612, 1613,and the unloading unit 1609 are combined into a single unitaryarrangement as an apparatus.

The substrate plating apparatus shown in FIG. 70 operates as follows: Asemiconductor substrate W is supplied from the substrate cassette 1601-1placed in the loading unit 1601 successively to one of the copperplating chambers 1602, 1602. In one of the copper plating chamber 1602,1602, a plated copper film is formed on a surface of a semiconductorsubstrate W having an interconnection region composed of aninterconnection trench and an interconnection hole (contact hole). Thetwo copper plating chambers 1602, 1602 are employed to allow thesemiconductor substrate W to be plated with a copper film for a longperiod of time. Specifically, the semiconductor substrate W may beplated with a primary copper film according to electroplating in one ofthe copper plating chamber 1602, and then plated with a secondary copperfilm according to electroless-plating in the other copper platingchamber 1602. The substrate plating apparatus may have more than twocopper plating chambers.

The semiconductor substrate W with the plated copper film formed thereonis cleaned by water in one of the water cleaning chambers 1603, 1604.Then, the chemical mechanical polishing unit 1605 removes the unwantedportion of the plated copper film from the surface of the semiconductorsubstrate W, leaving a portion of the plated copper film in theinterconnection trench and the interconnection hole.

Thereafter, the semiconductor substrate W with the remaining platedcopper film is transferred to the water cleaning chamber 1610, in whichthe semiconductor substrate W is cleaned with water. Then, thesemiconductor substrate W is transferred to the pretreatment chamber1611, and pretreated therein for the deposition of a protective platedlayer. The pretreated semiconductor substrate W is transferred to theprotective layer-plating chamber 1612. In the protective layer platingchamber 1612, a protective plated layer is formed on the plated copperfilm in the interconnection region on the semiconductor substrate W. Forexample, the protective plated layer is formed with an alloy of nickel(Ni) and boron (B) by electroless-plating.

After semiconductor substrate is cleaned in one of the water cleaningchamber 1613, 1614, an upper portion of the protective plated layerdeposited on the plated copper film is polished off to planarize theprotective plated layer, in the chemical mechanical polishing unit 1615,After the protective plated layer is polished, the semiconductorsubstrate W is cleaned by water in one of the water cleaning chambers1606, 1607, dried in the drying chamber 1608, and then transferred tothe substrate cassette 1609-1 in the unloading unit 1609.

FIG. 71 is a plan view of still another example of a substrate platingapparatus. As shown in FIG. 71, the substrate plating apparatus includesa robot 1616 at its center which has a robot arm 1616-1, and also has acopper plating chamber 1602, a pair of water cleaning chambers 1603,1604, a chemical mechanical polishing unit 1605, a pretreatment chamber1611, a protective layer plating chamber 1612, a drying chamber 1608,and a loading/unloading portion 1617 which are disposed around the robot1616 and positioned within the reach of the robot arm 1616-1. A loadingunit 1601 for loading semiconductor substrates and an unloading unit1609 for unloading semiconductor substrates is disposed adjacent to theloading/unloading portion 1617. The robot 1616, the chambers 1602, 1603,1604, the chemical mechanical polishing unit 1605, the chambers 1608,1611, 1612, the loading/unloading portion 1617, the loading unit 1601,and the unloading unit 1609 are combined into a single unitaryarrangement as an apparatus.

The substrate plating apparatus shown in FIG. 71 operates as follows:

A semiconductor substrate to be plated is transferred from the loadingunit 1601 to the loading/unloading portion 1617, from which thesemiconductor substrate is received by the robot arm 1616-1 andtransferred thereby to the copper plating chamber 1602. In the copperplating chamber 1602, a plated copper film is formed on a surface of thesemiconductor substrate which has an interconnection region composed ofan interconnection trench and an interconnection hole. The semiconductorsubstrate with the plated copper film formed thereon is transferred bythe robot arm 1616-1 to the chemical mechanical polishing unit 1605. Inthe chemical mechanical polishing unit 1605, the plated copper film isremoved from the surface of the semiconductor substrate W, leaving aportion of the plated copper film in the interconnection trench and theinterconnection hole.

The semiconductor substrate is then transferred by the robot arm 1616-1to the water-cleaning chamber 1604, in which the semiconductor substrateis cleaned by water. Thereafter, the semiconductor substrate istransferred by the robot arm 1616-1 to the pretreatment chamber 1611, inwhich the semiconductor substrate is pretreated therein for thedeposition of a protective plated layer. The pretreated semiconductorsubstrate is transferred by the robot arm 1616-1 to the protective layerplating chamber 1612. In the protective layer plating chamber 1612, aprotective plated layer is formed on the plated copper film in theinterconnection region on the semiconductor substrate W. Thesemiconductor substrate with the protective plated layer formed thereonis transferred by the robot arm 1616-1 to the water cleaning chamber1604, in which the semiconductor substrate is cleaned by water. Thecleaned semiconductor substrate is transferred by the robot arm 1616-1to the drying chamber 1608, in which the semiconductor substrate isdried. The dried semiconductor substrate is transferred by the robot arm1616-1 to the loading/unloading portion 1617, from which the platedsemiconductor substrate is transferred to the unloading unit 1609.

FIG. 72 is a view showing the plan constitution of another example of asemiconductor substrate processing apparatus. The semiconductorsubstrate processing apparatus is of a constitution in which there areprovided a loading/unloading section 1701, a copper plating unit 1702, afirst robot 1703, a third cleaning machine 1704, a reversing machine1705, a reversing machine 1706, a second cleaning machine 1707, a secondrobot 1708, a first cleaning machine 1709, a first polishing apparatus1710, and a second polishing apparatus 1711. A before-plating andafter-plating film thickness measuring instrument 1712 for measuring thefilm thicknesses before and after plating, and a dry state filmthickness measuring instrument 1713 for measuring the film thickness ofa semiconductor substrate W in a dry state after polishing are placednear the first robot 1703.

The first polishing apparatus (polishing unit) 1710 has a polishingtable 1710-1, a top ring 1710-2, a top ring head 1710-3, a filmthickness measuring instrument 1710-4, and a pusher 1710-5. The secondpolishing apparatus (polishing unit) 1711 has a polishing table 1711-1,a top ring 1711-2, a top ring head 1711-3, a film thickness measuringinstrument 1711-4, and a pusher 1711-5.

A cassette 1701-1 accommodating the semiconductor substrates W, in whicha via hole and a trench for interconnect are formed, and a seed layer isformed thereon is placed on a loading port of the loading/unloadingsection 1701. The first robot 1703 takes out the semiconductor substrateW from the cassette 1701-1, and carries the semiconductor substrate Winto the copper plating unit 1702 where a plated Cu film is formed. Atthis time, the film thickness of the seed layer is measured with thebefore-plating and after-plating film thickness measuring instrument1712. The plated Cu film is formed by carrying out hydrophilic treatmentof the face of the semiconductor substrate W, and then Cu plating. Afterformation of the plated Cu film, rinsing or cleaning of thesemiconductor substrate W is carried out in the copper plating unit1702.

When the semiconductor substrate W is taken out from the copper platingunit 1702 by the first robot 1703, the film thickness of the plated Cufilm is measured with the before-plating and after-plating filmthickness measuring instrument 1712. The results of its measurement arerecorded into a recording device (not shown) as record data on thesemiconductor substrate, and are used for judgment of an abnormality ofthe copper plating unit 1702. After measurement of the film thickness,the first robot 1703 transfers the semiconductor substrate W to thereversing machine 1705, and the reversing machine 1705 reverses thesemiconductor substrate W (the surface on which the plated Cu film hasbeen formed faces downward). The first polishing apparatus 1710 and thesecond polishing apparatus 1711 perform polishing in a serial mode and aparallel mode. Next, polishing in the serial mode will be described.

In the serial mode polishing, a primary polishing is performed by thepolishing apparatus 1710, and a secondary polishing is performed by thepolishing apparatus 1711. The second robot 1708 picks up thesemiconductor substrate W on the reversing machine 1705, and places thesemiconductor substrate W on the pusher 1710-5 of the polishingapparatus 1710. The top ring 1710-2 attracts the semiconductor substrateW on the pusher 1710-5 by suction, and brings the surface of the platedCu film of the semiconductor substrate W into contact with a polishingsurface of the polishing table 1710-1 under pressure to perform aprimary polishing. With the primary polishing, the plated Cu film isbasically polished. The polishing surface of the polishing table 1710-1is composed of foamed polyurethane such as IC1000, or a material havingabrasive grains fixed thereto or impregnated therein. Upon relativemovements of the polishing surface and the semiconductor substrate W,the plated Cu film is polished.

After completion of polishing of the plated Cu film, the semiconductorsubstrate W is returned onto the pusher 1710-5 by the top ring 1710-2.The second robot 1708 picks up the semiconductor substrate W, andintroduces it into the first cleaning machine 1709. At this time, achemical liquid may be ejected toward the face and backside of thesemiconductor substrate W on the pusher 1710-5 to remove particlestherefrom or cause particles to be difficult to adhere thereto.

After completion of cleaning in the first cleaning machine 1709, thesecond robot 1708 picks up the semiconductor substrate W, and places thesemiconductor substrate W on the pusher 1711-5 of the second polishingapparatus 1711. The top ring 1711-2 attracts the semiconductor substrateW on the pusher 1711-5 by suction, and brings the surface of thesemiconductor substrate W, which has the barrier layer formed thereon,into contact with a polishing surface of the polishing table 1711-1under pressure to perform the secondary polishing. The constitution ofthe polishing table is the same as the top ring 1711-2. With thissecondary polishing, the barrier layer is polished. However, there maybe a case in which a Cu film and an oxide film left after the primarypolishing are also polished.

A polishing surface of the polishing table 1711-1 is composed of foamedpolyurethane such as IC1000, or a material having abrasive grains fixedthereto or impregnated therein. Upon relative movements of the polishingsurface and the semiconductor substrate W, polishing is carried out. Atthis time, silica, alumina, ceria, on the like is used as abrasivegrains or a slurry. A chemical liquid is adjusted depending on the typeof the film to be polished.

Detection of an end point of the secondary polishing is performed bymeasuring the film thickness of the barrier layer mainly with the use ofthe optical film thickness measuring instrument, and detecting the filmthickness which has become zero, or the surface of an insulating filmcomprising SiO₂ shows up. Furthermore, a film thickness measuringinstrument with an image processing function is used as the filmthickness measuring instrument 1711-4 provided near the polishing table1711-1. By use of this measuring instrument, measurement of the oxidefilm is made, the results are stored as processing records of thesemiconductor substrate W, and used for judging whether thesemiconductor substrate W in which secondary polishing has been finishedcan be transferred to a subsequent step or not. If the end point of thesecondary polishing is not reached, repolishing is performed. Ifover-polishing has been performed beyond a prescribed value due to anyabnormality, then the semiconductor substrate processing apparatus isstopped to avoid next polishing so that defective products will notincrease.

After completion of the secondary polishing, the semiconductor substrateW is moved to the pusher 1711-5 by the top ring 1711-2. The second robot1708 picks up the semiconductor substrate W on the pusher 1711-5. Atthis time, a chemical liquid may be ejected toward the face and backsideof the semiconductor substrate W on the pusher 1711-5 to removeparticles therefrom or cause particles to be difficult to adherethereto.

The second robot 1708 carries the semiconductor substrate W into thesecond cleaning machine 1707 where cleaning of the semiconductorsubstrate W is performed. The constitution of the second cleaningmachine 1707 is also the same as the constitution of the first cleaningmachine 1709. The face of the semiconductor substrate W is scrubbed withthe PVA sponge rolls using a cleaning liquid comprising pure water towhich a surface active agent, a chelating agent, or a pH regulatingagent is added. A strong chemical liquid such as DHF is ejected from anozzle toward the backside of the semiconductor substrate W to performetching of the diffused Cu thereon. If there is no problem of diffusion,scrubbing cleaning is performed with the PVA sponge rolls using the samechemical liquid as that used for the face.

After completion of the above cleaning, the second robot 1708 picks upthe semiconductor substrate W and transfers it to the reversing machine1706, and the reversing machine 1706 reverses the semiconductorsubstrate W. The semiconductor substrate W which has been reversed ispicked up by the first robot 1703, and transferred to the third cleaningmachine 1704. In the third cleaning machine 1704, megasonic waterexcited by ultrasonic vibrations is ejected toward the face of thesemiconductor substrate W to clean the semiconductor substrate W. Atthis time, the face of the semiconductor substrate W may be cleaned witha known pencil type sponge using a cleaning liquid comprising pure waterto which a surface active agent, a chelating agent, or a pH regulatingagent is added. Thereafter, the semiconductor substrate w is dried byspin-drying.

As described above, if the film thickness has been measured with thefilm thickness measuring instrument 1711-4 provided near the polishingtable 1711-1, then the semiconductor substrate W is not subjected tofurther process and is accommodated into the cassette placed on theunloading port of the loading/unloading section 1771.

FIG. 73 is a view showing the plan constitution of another example of asemiconductor substrate processing apparatus. The substrate processingapparatus differs from the substrate processing apparatus shown in FIG.72 in that a cap-plating unit 1750 is provided instead of the copperplating unit 1702 in FIG. 72.

A cassette 1701-1 accommodating the semiconductor substrates W formedplated Cu film is placed on a load port of a loading/unloading section1701. The semiconductor substrate W taken out from the cassette 1701-1is transferred to the first polishing apparatus 1710 or second polishingapparatus 1711 in which the surface of the plated Cu film is polished.After completion of polishing of the plated Cu film, the semiconductorsubstrate W is cleaned in the first cleaning machine 1709.

After completion of cleaning in the first cleaning machine 1709, thesemiconductor substrate W is transferred to the cap-plating unit 1750where cap-plating is applied onto the surface of the plated Cu film withthe aim of preventing oxidation of plated Cu film due to the atmosphere.The semiconductor substrate to which cap-plating has been applied iscarried by the second robot 1708 from the cap-plating unit 1750 to thesecond cleaning unit 1707 where it is cleaned with pure water ordeionized water. The semiconductor substrate after completion ofcleaning is returned into the cassette 1701-1 placed on theloading/unloading section 1701.

FIG. 74 is a view showing the plan constitution of still another exampleof a semiconductor substrate processing apparatus. The substrateprocessing apparatus differs from the substrate processing apparatusshown in FIG. 73 in that an annealing unit 1751 is provided instead ofthe third cleaning machine 1709 in FIG. 73.

The semiconductor substrate W, which is polished in the polishing unit1710 or 1711, and cleaned in the first cleaning machine 1709 describedabove, is transferred to the cap-plating unit 1750 where cap-plating isapplied onto the surface of the plated Cu film. The semiconductorsubstrate to which cap-plating has been applied is carried by the secondrobot 1732 from the cap-plating unit 1750 to the first cleaning unit1707 where it is cleaned.

After completion of cleaning in the first cleaning machine 1709, thesemiconductor substrate W is transferred to the annealing unit 1751 inwhich the substrate is annealed, whereby the plated Cu film is alloyedso as to increase the electromigration resistance of the plated Cu film.The semiconductor substrate W to which annealing treatment has beenapplied is carried from the annealing unit 1751 to the second cleaningunit 1707 where it is cleaned with pure water or deionized water. Thesemiconductor substrate W after completion of cleaning is returned intothe cassette 1701-1 placed on the loading/unloading section 1701.

FIG. 75 is a view showing a plan layout constitution of another exampleof the substrate processing apparatus. In FIG. 75, portions denoted bythe same reference numerals as those in FIG. 72 show the same orcorresponding portions. In the substrate processing apparatus, a pusherindexer 1725 is disposed close to a first polishing apparatus 1710 and asecond polishing apparatus 1711. Substrate placing tables 1721, 1722 aredisposed close to a third cleaning machine 1704 and a copper platingunit 1702, respectively. A robot 1723 is disposed close to a firstcleaning machine 1709 and the third cleaning machine 1704. Further, arobot 1724 is disposed close to a second cleaning machine 1707 and thecopper plating unit 1702, and a dry state film thickness measuringinstrument 1713 is disposed close to a loading/unloading section 1701and a first robot 1703.

In the substrate processing apparatus of the above constitution, thefirst robot 1703 takes out a semiconductor substrate W from a cassette1701-1 placed on the load port of the loading/unloading section 1701.After the film thicknesses of a barrier layer and a seed layer aremeasured with the dry state film thickness measuring instrument 1713,the first robot 1703 places the semiconductor substrate W on thesubstrate placing table 1721. In the case where the dry state filmthickness measuring instrument 1713 is provided on the hand of the firstrobot 1703, the film thicknesses are measured thereon, and the substrateis placed on the substrate placing table 1721. The second robot 1723transfers the semiconductor substrate W on the substrate placing table1721 to the copper plating unit 1702 in which a plated Cu film isformed. After formation of the plated Cu film, the film thickness of theplated Cu film is measured with a before-plating and after-plating filmthickness measuring instrument 1712. Then, the second robot 1723transfers the semiconductor substrate W to the pusher indexer 1725 andloads it thereon.

[Serial Mode]

In the serial mode, a top ring head 1710-2 holds the semiconductorsubstrate W on the pusher indexer 1725 by suction, transfers it to apolishing table 1710-1, and presses the semiconductor substrate Wagainst a polishing surface on the polishing table 1710-1 to performpolishing. Detection of the end point of polishing is performed by thesame method as described above. The semiconductor substrate W aftercompletion of polishing is transferred to the pusher indexer 1725 by thetop ring head 1710-2, and loaded thereon. The second robot 1723 takesout the semiconductor substrate W, and carries it into the firstcleaning machine 1709 for cleaning. Then, the semiconductor substrate Wis transferred to the pusher indexer 1725, and loaded thereon.

A top ring head 1711-2 holds the semiconductor substrate W on the pusherindexer 1725 by suction, transfers it to a polishing table 1711-1, andpresses the semiconductor substrate W against a polishing surface on thepolishing table 1711-1 to perform polishing. Detection of the end pointof polishing is performed by the same method as described above. Thesemiconductor substrate W after completion of polishing is transferredto the pusher indexer 1725 by the top ring head 1711-2, and loadedthereon. The third robot 1724 picks up the semiconductor substrate W,and its film thickness is measured with a film thickness measuringinstrument 1726. Then, the semiconductor substrate W is carried into thesecond cleaning machine 1707 for cleaning. Thereafter, the semiconductorsubstrate W is carried into the third cleaning machine 1704, where it iscleaned and then dried by spin-drying. Then, the semiconductor substrateW is picked up by the third robot 1724, and placed on the substrateplacing table 1722.

[Parallel Mode]

In the parallel mode, the top ring head 1710-2 or 1711-2 holds thesemiconductor substrate W on the pusher indexer 1725 by suction,transfers it to the polishing table 1710-1 or 1711-1, and presses thesemiconductor substrate W against the polishing surface on the polishingtable 1710-1 or 1711-1 to perform polishing. After measurement of thefilm thickness, the third robot 1724 picks up the semiconductorsubstrate W, and places it on the substrate placing table 1722.

The first robot 1703 transfers the semiconductor substrate W on thesubstrate placing table 1722 to the dry state film thickness measuringinstrument 1713. After the film thickness is measured, the semiconductorsubstrate W is returned to the cassette 1701-1 of the loading/unloadingsection 1701.

FIG. 76 is a view showing another plan layout constitution of thesubstrate processing apparatus. The substrate processing apparatus issuch a substrate processing apparatus which forms a seed layer and aplated Cu film on a semiconductor substrate W having no seed layerformed thereon, and polishes these films to form interconnects.

In the substrate polishing apparatus, a pusher indexer 1725 is disposedclose to a first polishing apparatus 1710 and a second polishingapparatus 1711, substrate placing tables 1721, 1722 are disposed closeto a second cleaning machine 1707 and a seed layer forming unit 1727,respectively, and a robot 1723 is disposed close to the seed layerforming unit 1727 and a copper plating unit 1702. Further, a robot 1724is disposed close to a first cleaning machine 1709 and the secondcleaning machine 1707, and a dry state film thickness measuringinstrument 1713 is disposed close to a loading/unloading section 1701and a first robot 1702.

The first robot 1703 takes out a semiconductor substrate W having abarrier layer thereon from a cassette 1701-1 placed on the load port ofthe loading/unloading section 1701, and places it on the substrateplacing table 1721. Then, the second robot 1723 transports thesemiconductor substrate W to the seed layer forming unit 1727 where aseed layer is formed. The seed layer is formed by electroless-plating.The second robot 1723 enables the semiconductor substrate having theseed layer formed thereon to be measured in thickness of the seed layerby the before-plating and after-plating film thickness measuringinstrument 1712. After measurement of the film thickness, thesemiconductor substrate is carried into the copper plating unit 1702where a plated Cu film is formed.

After formation of the plated Cu film, its film thickness is measured,and the semiconductor substrate is transferred to a pusher indexer 1725.A top ring 1710-2 or 1711-2 holds the semiconductor substrate W on thepusher indexer 1725 by suction, and transfers it to a polishing table1710-1 or 1711-1 to perform polishing. After polishing, the top ring1710-2 or 1711-2 transfers the semiconductor substrate W to a filmthickness measuring instrument 1710-4 or 1711-4 to measure the filmthickness. Then, the top ring 1710-2 or 1711-2 transfers thesemiconductor substrate W to the pusher indexer 1725, and places itthereon.

Then, the third robot 1724 picks up the semiconductor substrate W fromthe pusher indexer 1725, and carries it into the first cleaning machine1709. The third robot 1724 picks up the cleaned semiconductor substrateW from the first cleaning machine 1709, carries it into the secondcleaning machine 1707, and places the cleaned and dried semiconductorsubstrate on the substrate placing table 1722. Then, the first robot1703 picks up the semiconductor substrate W, and transfers it to the drystate film thickness measuring instrument 1713 in which the filmthickness is measured, and the first robot 1703 carries it into thecassette 1701-1 placed on the unload port of the loading/unloadingsection 1701.

In the substrate processing apparatus shown in FIG. 76, interconnectsare formed by forming a barrier layer, a seed layer and a plated Cu filmon a semiconductor substrate W having a via hole or a trench of acircuit pattern formed therein, and polishing them.

The cassette 1701-1 accommodating the semiconductor substrates W beforeformation of the barrier layer is placed on the load port of theloading/unloading section 1701. The first robot 1703 takes out thesemiconductor substrate W from the cassette 1701-1 placed on the loadport of the loading/unloading section 1701, and places it on thesubstrate placing table 1721. Then, the second robot 1723 transports thesemiconductor substrate W to the seed layer forming unit 1727 where abarrier layer and a seed layer are formed. The barrier layer and theseed layer are formed by electroless-plating. The second robot 1723brings the semiconductor substrate W having the barrier layer and theseed layer formed thereon to the before-plating and after-plating filmthickness measuring instrument 1712 which measures the film thicknessesof the barrier layer and the seed layer. After measurement of the filmthicknesses, the semiconductor substrate W is carried into the copperplating unit 1702 where a plated Cu film is formed.

FIG. 77 is a view showing plan layout constitution of another example ofthe substrate processing apparatus. In the substrate processingapparatus, there are provided a barrier layer forming unit 1811, a seedlayer forming unit 1812, a plating unit 1813, an annealing unit 1814, afirst cleaning unit 1815, a bevel and backside cleaning unit 1816, acap-plating unit 1817, a second cleaning unit 1818, a first aligner andfilm thickness measuring instrument 1841, a second aligner and filmthickness measuring instrument 1842, a first substrate reversing machine1843, a second substrate reversing machine 1844, a substrate temporaryplacing table 1845, a third film thickness measuring instrument 1846, aloading/unloading section 1820, a first polishing apparatus 1821, asecond polishing apparatus 1822, a first robot 1831, a second robot1832, a third robot 1833, and a fourth robot 1834. The film thicknessmeasuring instruments 1841, 1842, and 1846 are units, have the same sizeas the frontage dimension of other units (plating, cleaning, annealingunits, and the like), and are thus interchangeable.

In this example, an electroless Ru plating apparatus can be used as thebarrier layer forming unit 1811, an electroless Cu plating apparatus asthe seed layer forming unit 1812, and an electroplating apparatus as theplating unit 1813.

FIG. 78 is a flow chart showing the flow of the respective steps in thepresent substrate processing apparatus. The respective steps in theapparatus will be described according to this flow chart. First, asemiconductor substrate taken out by the first robot 1831 from acassette 1820 a placed on the load and unload unit 1820 is placed in thefirst aligner and film thickness measuring unit 1841, in such a statethat its surface, to be plated, faces upward. In order to set areference point for a position at which film thickness measurement ismade, notch alignment for film thickness measurement is performed, andthen film thickness data on the semiconductor substrate before formationof a Cu film are obtained.

Then, the semiconductor substrate is transported to the barrier layerforming unit 1811 by the first robot 1831. The barrier layer formingunit 1811 is such an apparatus for forming a barrier layer on thesemiconductor substrate by electroless Ru plating, and the barrier layerforming unit 1811 forms an Ru film as a film for preventing Cu fromdiffusing into an interlayer insulator film (e.g. SiO₂) of asemiconductor device. The semiconductor substrate discharged aftercleaning/drying steps is transported by the first robot 1831 to thefirst aligner and film thickness measuring unit 1841, where the filmthickness of the semiconductor substrate, i.e., the film thickness ofthe barrier layer is measured.

The semiconductor substrate after film thickness measurement is carriedinto the seed layer forming unit 1812 by the second robot 1832, and aseed layer is formed on the barrier layer by electroless Cu plating. Thesemiconductor substrate discharged after cleaning/drying steps istransported by the second robot 1832 to the second aligner and filmthickness measuring instrument 1842 for determination of a notchposition, before the semiconductor substrate is transported to theplating unit 1813, which is an impregnation plating unit, and then notchalignment for Cu plating is performed by the film thickness measuringinstrument 1842. If necessary, the film thickness of the semiconductorsubstrate before formation of a Cu film may be measured again in thefilm thickness measuring instrument 1842.

The semiconductor substrate which has completed notch alignment istransported by the third robot 1833 to the plating unit 1813 where Cuplating is applied to the semiconductor substrate. The semiconductorsubstrate discharged after cleaning/drying steps is transported by thethird robot 1833 to the bevel and backside cleaning unit 1816 where anunnecessary Cu film (seed layer) at a peripheral portion of thesemiconductor substrate is removed. In the bevel and backside cleaningunit 1816, the bevel is etched in a preset time, and Cu adhering to thebackside of the semiconductor substrate is cleaned with a chemicalliquid such as hydrofluoric acid. At this time, before transporting thesemiconductor substrate to the bevel and backside cleaning unit 1816,film thickness measurement of the semiconductor substrate may be made bythe second aligner and film thickness measuring instrument 1842 toobtain the thickness value of the Cu film formed by plating, and basedon the obtained results, the bevel etching time may be changedarbitrarily to carry out etching. The region etched by bevel etching isa region which corresponds to a peripheral edge portion of the substrateand has no circuit formed therein, or a region which is not utilizedfinally as a chip although a circuit is formed. A bevel portion isincluded in this region.

The semiconductor substrate discharged after cleaning/drying steps inthe bevel and backside cleaning unit 1816 is transported by the thirdrobot 1833 to the substrate reversing machine 1843. After thesemiconductor substrate is turned over by the substrate reversingmachine 1843 to cause the plated surface to be directed downward, thesemiconductor substrate is introduced into the annealing unit 1814 bythe fourth robot 1834 for thereby stabilizing an interconnectionportion. Before and/or after annealing treatment, the semiconductorsubstrate is carried into the second aligner and film thicknessmeasuring unit 1842 where the film thickness of a copper film formed onthe semiconductor substrate is measured. Then, the semiconductorsubstrate is carried by the fourth robot 1834 into the first polishingapparatus 1821 in which the Cu film and the seed layer of thesemiconductor substrate are polished.

At this time, desired abrasive grains or the like are used, but fixedabrasive may be used in order to prevent dishing and enhance flatness ofthe face. After completion of primary polishing, the semiconductorsubstrate is transported by the fourth robot 1834 to the first cleaningunit 1815 where it is cleaned. This cleaning is scrub-cleaning in whichrolls having substantially the same length as the diameter of thesemiconductor substrate are placed on the face and the backside of thesemiconductor substrate, and the semiconductor substrate and the rollsare rotated, while pure water or deionized water is flowed, therebyperforming cleaning of the semiconductor substrate.

After completion of the primary cleaning, the semiconductor substrate istransported by the fourth robot 1834 to the second polishing apparatus1822 where the barrier layer on the semiconductor substrate is polished.At this time, desired abrasive grains or the like are used, but fixedabrasive may be used in order to prevent dishing and enhance flatness ofthe face. After completion of secondary polishing, the semiconductorsubstrate is transported by the fourth robot 1834 again to the firstcleaning unit 1815 where scrub-cleaning is performed. After completionof cleaning, the semiconductor substrate is transported by the fourthrobot 1834 to the second substrate reversing machine 1844 where thesemiconductor substrate is reversed to cause the plated surface to bedirected upward, and then the semiconductor substrate is placed on thesubstrate temporary placing table 1845 by the third robot.

The semiconductor substrate is transported by the second robot 1832 fromthe substrate temporary placing table 1845 to the cap-plating unit 1817where cap-plating is applied onto the Cu surface with the aim ofpreventing oxidation of Cu due to the atmosphere. The semiconductorsubstrate to which cap-plating has been applied is carried by the secondrobot 1832 from the cover plating unit 1817 to the third film thicknessmeasuring instrument 146 where the thickness of the copper film ismeasured. Thereafter, the semiconductor substrate is carried by thefirst robot 1831 into the second cleaning unit 1818 where it is cleanedwith pure water or deionized water. The semiconductor substrate aftercompletion of cleaning is returned into the cassette 1820 a placed onthe loading/unloading section 1820.

In this manner, shown in FIG. 95A through 95C, interconnects made ofcopper is formed, thereafter a protective layer is formed on theinterconnects selectively by electroless cap-plating for protecting theinterconnects.

Specifically, as shown in FIG. 95A, an insulating film 2 of SiO₂ isdeposited on a conductive layer 1 a of a substrate 1 on whichsemiconductor devices are formed, a contact hole 3 and a trench 4 for aninterconnect are formed by lithography and etching technology, a barrierlayer 5 comprising TiN or the like is formed thereon, and a seed layer 7is further formed thereon.

Then, as shown in FIG. 95B, copper plating is applied onto the surfaceof the semiconductor substrate W to fill copper into the contact hole 3and the trench 4 of the semiconductor substrate W and deposit a copperfilm 6 on the insulating film 2. Thereafter, the copper film 6 on theinsulating film 2 is removed by chemical mechanical polishing (CMP) tomake the surface of the copper film 6, filled into the contact hole 3and the trench 4 for an interconnect, flush with the surface of theinsulating film 2, as shown in FIG. 95C. An interconnect protectivelayer 8 is formed on the exposed metal surface.

In this case, the seed layer 7 may be reinforced so as to become acomplete layer without a thin portion. FIG. 94 is a flow diagram showingthe flow of reinforcing process steps.

First, the substrate W having a seed layer 7 (see FIG. 95A) istransported to a pre-plating unit comprising an electroplating unit oran electroless-plating unit for depositing an additional metal on theseed layer 7 (step 1).

Next, the first-stage plating (pre-plating) is carried out in theelectroplating unit or the electroless-plating unit, thereby reinforcingand completing the thin portion of the seed layer 7 (step 2).

After the completion of the first-stage plating, the substrate W is,according to necessity, transported to the washing section for washingby water (step 3), and is then transported a plating unit for fillingthe metal in the trenches.

Next, the second-stage plating is performed onto the surface of thesubstrate W in the plating unit, thereby effecting filling with copper(step 4). Since the seed layer 7 has been reinforced by the first-stageplating to become a complete layer without a thin portion, electriccurrent flows evenly through the seed layer 7 in the second-stageplating, whereby the filling with copper can be completed without theformation of any voids.

After the completion of the second-stage plating, the substrate W is,according to necessity, transported to the washing section for washingby water (step 5). Thereafter, the substrate W is transported to thebevel-etching/chemical cleaning unit where the substrate W is cleaned byusing a chemical liquid, and a thin copper film, etc. formed on thebevel portion of the substrate W is etched away (step 6). The substrateis then transported to the cleaning/drying section for cleaning anddrying (step 7). Thereafter, the substrate is returned to the cassetteof the loading/unloading section by the first transporting device (step8).

An electrolytic plating process for plating a semiconductor substrate Wshown in FIG. 95A will be described bellow.

A first plating process is performed by immersing the semiconductorsubstrate W into a first plating liquid, such as a high throwing powercopper sulfate plating liquid used for printed circuit boards. Thisprocess forms a uniform initial thin plated film over the entire surfaceof the trenches formed in the surface of the semiconductor substrate W,wherein the surface includes the bottom and side walls of the trenches.Here, the high throwing power copper sulfate solution has a lowconcentration of copper sulfate, a high concentration of sulfuric acid,and is superior in throwing power and coating uniformity. An examplecomposition of this solution is 5–100 g/l of copper sulfate and 100–250g/l of sulfuric acid.

Since the plating liquid has a low concentration of copper sulfate and ahigh concentration of sulfuric acid, the conductivity of the solution ishigh and the polarization is great, thereby improving throwing power. Asa result, plating metal is uniformly deposited on the surface of thesemiconductor substrate W, eliminating unplated areas formed on the sideand bottom surfaces of the fine trench.

After washing the semiconductor substrate W, a second plating process isperformed by immersing the semiconductor substrate W into a secondplating liquid, such as a copper sulfate plating liquid for decorativeuses. This process fills copper into the trenches and forms a platedfilm having a flat surface on the surface of the substrate. Here, thecopper sulfate plating liquid has a high concentration of copper sulfateand a low concentration of sulfuric acid and is superior in levelingability. An example composition of the solution is 100–300 g/l of coppersulfate and 10–100 g/l of sulfuric acid.

Here, leveling ability defines a quality describing the degree ofsmoothness on the plating surface.

The pre-plating unit comprising an electroplating unit or anelectroless-plating may be placed in the electroplating apparatus.

The aligner and film thickness measuring instrument 1841 and the alignerand film thickness measuring instrument 1842 perform positioning of thenotch portion of the substrate and measurement of the film thickness.

The seed layer forming unit 1812 may be omitted. In this case, a platedfilm may be formed on a barrier layer directly in a plating unit 1813.

The seed layer forming unit may be comprises an electroplating unit oran electoroless-plating unit. In this case, a seed layer made of copperfilm, for example, is formed on the barrier layer by electroplating orelectoroless-plating, thereafter a plated film may be formed on abarrier layer in a plating unit 1813.

The bevel and backside cleaning unit 1816 can perform an edge (bevel) Cuetching and a backside cleaning at the same time, and can suppressgrowth of a natural oxide film of copper at the circuit formationportion on the surface of the substrate. FIG. 79 shows a schematic viewof the bevel and backside cleaning unit 1816. As shown in FIG. 79, thebevel and backside cleaning unit 1816 has a substrate holding portion1922 positioned inside a bottomed cylindrical waterproof cover 1920 andadapted to rotate a substrate W at a high speed, in such a state thatthe face of the substrate W faces upwardly, while holding the substrateW horizontally by spin chucks 1921 at a plurality of locations along acircumferential direction of a peripheral edge portion of the substrate;a center nozzle 1924 placed above a nearly central portion of the faceof the substrate W held by the substrate holding portion 1922; and anedge nozzle 1926 placed above the peripheral edge portion of thesubstrate W. The center nozzle 1924 and the edge nozzle 1926 aredirected downward. A back nozzle 1928 is positioned below a nearlycentral portion of the backside of the substrate W, and directed upward.The edge nozzle 1926 is adapted to be movable in a diametrical directionand a height direction of the substrate W.

The width of movement L of the edge nozzle 1926 is set such that theedge nozzle 1926 can be arbitrarily positioned in a direction toward thecenter from the outer peripheral end surface of the substrate, and a setvalue for L is inputted according to the size, usage, or the like of thesubstrate W. Normally, an edge cut width C is set in the range of 2 mmto 5 mm. In the case where a rotational speed of the substrate is acertain value or higher at which the amount of liquid migration from thebackside to the face is not problematic, the copper film within the edgecut width C can be removed.

Next, the method of cleaning with this cleaning apparatus will bedescribed. First, the semiconductor substrate W is horizontally rotatedintegrally with the substrate holding portion 1922, with the substratebeing held horizontally by the spin chucks 1921 of the substrate holdingportion 1922. In this state, an acid solution is supplied from thecenter nozzle 1924 to the central portion of the face of the substrateW. The acid solution may be a non-oxidizing acid, and hydrofluoric acid,hydrochloric acid, sulfuric acid, citric acid, oxalic acid, or the likeis used. On the other hand, an oxidizing agent solution is suppliedcontinuously or intermittently from the edge nozzle 1926 to theperipheral edge portion of the substrate W. As the oxidizing agentsolution, one of an aqueous solution of ozone, an aqueous solution ofhydrogen peroxide, an aqueous solution of nitric acid, and an aqueoussolution of sodium hypochlorite is used, or a combination of these isused.

In this manner, the copper film, or the like formed on the upper surfaceand end surface in the region of the peripheral edge portion C of thesemiconductor substrate W is rapidly oxidized with the oxidizing agentsolution, and is simultaneously etched with the acid solution suppliedfrom the center nozzle 1924 and spread on the entire face of thesubstrate, whereby it is dissolved and removed. By mixing the acidsolution and the oxidizing agent solution at the peripheral edge portionof the substrate, a steep etching profile can be obtained, in comparisonwith a mixture of them which is produced in advance being supplied. Atthis time, the copper etching rate is determined by theirconcentrations. If a natural oxide film of copper is formed in thecircuit-formed portion on the face of the substrate, this natural oxideis immediately removed by the acid solution spreading on the entire faceof the substrate according to rotation of the substrate, and does notgrow any more. After the supply of the acid solution from the centernozzle 1924 is stopped, the supply of the oxidizing agent solution fromthe edge nozzle 1926 is stopped. As a result, silicon exposed on thesurface is oxidized, and deposition of copper can be suppressed.

On the other hand, an oxidizing agent solution and a silicon oxide filmetching agent are supplied simultaneously or alternately from the backnozzle 1928 to the central portion of the backside of the substrate.Therefore, copper or the like adhering in a metal form to the backsideof the semiconductor substrate W can be oxidized with the oxidizingagent solution, together with silicon of the substrate, and can beetched and removed with the silicon oxide film etching agent. Thisoxidizing agent solution is preferably the same as the oxidizing agentsolution supplied to the face, because the types of chemicals aredecreased in number. Hydrofluoric acid can be used as the silicon oxidefilm etching agent, and if hydrofluoric acid is used as the acidsolution on the face of the substrate, the types of chemicals can bedecreased in number. Thus, if the supply of the oxidizing agent isstopped first, a hydrophobic surface is obtained. If the etching agentsolution is stopped first, a water-saturated surface (a hydrophilicsurface) is obtained, and thus the backside surface can be adjusted to acondition which will satisfy the requirements of a subsequent process.

In this manner, the acid solution, i.e., etching solution is supplied tothe substrate to remove metal ions remaining on the surface of thesubstrate W. Then, pure water is supplied to replace the etchingsolution with pure water and remove the etching solution, and then thesubstrate is dried by spin-drying. In this way, removal of the copperfilm in the edge cut width C at the peripheral edge portion on the faceof the semiconductor substrate, and removal of copper contaminants onthe backside are performed simultaneously to thus allow this treatmentto be completed, for example, within 80 seconds. The etching cut widthof the edge can be set arbitrarily (to 2 mm to 5 mm), but the timerequired for etching does not depend on the cut width.

Annealing treatment performed before the CMP process and after platinghas a favorable effect on the subsequent CMP treatment and on theelectrical characteristics of interconnection. Observation of thesurface of broad interconnection (unit of several micrometers) after theCMP treatment without annealing showed many defects such as microvoids,which resulted in an increase in the electrical resistance of the entireinterconnection. Execution of annealing ameliorated the increase in theelectrical resistance. In the absence of annealing, thin interconnectionshowed no voids. Thus, the degree of grain growth is presumed to beinvolved in these phenomena. That is, the following mechanism can bespeculated: Grain growth is difficult to occur in thin interconnection.In broad interconnection, on the other hand, grain growth proceeds inaccordance with annealing treatment. During the process of grain growth,ultrafine pores in the plated film, which are too small to be seen bythe SEM (scanning electron microscope), gather and move upward, thusforming microvoid-like depressions in the upper part of theinterconnection. The annealing conditions in the annealing unit 1814 aresuch that hydrogen (2% or less) is added in a gas atmosphere, thetemperature is in the range of 300° C. to 400° C., and the time is inthe range of 1 to 5 minutes. Under these conditions, the above effectswere obtained.

FIGS. 82 and 83 show the annealing unit 1814. The annealing unit 1814comprises a chamber 1002 having a gate 1000 for taking in and taking outthe semiconductor substrate W, a hot plate 1004 disposed at an upperposition in the chamber 1002 for heating the semiconductor substrate Wto e.g. 400° C., and a cool plate 1006 disposed at a lower position inthe chamber 1002 for cooling the semiconductor substrate W by, forexample, flowing a cooling water inside the plate. The annealing unit1002 also has a plurality of vertically movable elevating pins 1008penetrating the cool plate 1006 and extending upward and downwardtherethrough for placing and holding the semiconductor substrate W onthem. The annealing unit further includes a gas introduction pipe 1010for introducing an antioxidant gas between the semiconductor substrate Wand the hot plate 1004 during annealing, and a gas discharge pipe 1012for discharging the gas which has been introduced from the gasintroduction pipe 1010 and flowed between the semiconductor substrate Wand the hot plate 1004. The pipes 1010 and 1012 are disposed on theopposite sides of the hot plate 1004.

The gas introduction pipe 1010 is connected to a mixed gas introductionline 1022 which in turn is connected to a mixer 1020 where a N₂ gasintroduced through a N₂ gas introduction line 1016 containing a filter1014 a, and a H₂ gas introduced through a H₂ gas introduction line 1018containing a filter 1014 b, are mixed to form a mixed gas which flowsthrough the line 1022 into the gas introduction pipe 1010.

In operation, the semiconductor substrate W, which has been carried inthe chamber 1002 through the gate 1000, is held on the elevating pins1008 and the elevating pins 1008 are raised up to a position at whichthe distance between the semiconductor substrate W held on the liftingpins 1008 and the hot plate 1004 becomes e.g. 0.1–1.0 mm. In this state,the semiconductor substrate W is then heated to e.g. 400° C. through thehot plate 1004 and, at the same time, the antioxidant gas is introducedfrom the gas introduction pipe 1010 and the gas is allowed to flowbetween the semiconductor substrate W and the hot plate 1004 while thegas is discharged from the gas discharge pipe 1012, thereby annealingthe semiconductor substrate W while preventing its oxidation. Theannealing treatment may be completed in about several tens of seconds to60 seconds. The heating temperature of the substrate may be selected inthe range of 100–600° C.

After the completion of the annealing, the elevating pins 1008 arelowered down to a position at which the distance between thesemiconductor substrate W held on the elevating pins 1008 and the coolplate 1006 becomes e.g. 0–0.5 mm. In this state, by introducing acooling water into the cool plate 1006, the semiconductor substrate W iscooled by the cool plate to a temperature of 100° C. or lower in e.g.10–60 seconds. The cooled semiconductor substrate is sent to the nextstep.

A mixed gas of N₂ gas with several % of H₂ gas is used as the aboveantioxidant gas. However, N₂ gas may be used singly.

The annealing unit may be placed in the electroplating apparatus.

FIG. 80 is a schematic constitution drawing of the electroless-platingapparatus. As shown in FIG. 80, this electroless-plating apparatuscomprises holding means 1911 for holding a semiconductor substrate W tobe plated on its upper surface, a dam member 1931 for contacting aperipheral edge portion of a surface to be plated (upper surface) of thesemiconductor substrate W held by the holding means 1911 to seal theperipheral edge portion, and a shower head 1941 for supplying a platingliquid to the surface, to be plated, of the semiconductor substrate Whaving the peripheral edge portion sealed with the dam member 1931. Theelectroless-plating apparatus further comprises cleaning liquid supplymeans 1951 disposed near an upper outer periphery of the holding means1911 for supplying a cleaning liquid to the surface, to be plated, ofthe semiconductor substrate W, a recovery vessel 1961 for recovering acleaning liquid or the like (plating waste liquid) discharged, a platingliquid recovery nozzle 1965 for sucking in and recovering the platingliquid held on the semiconductor substrate W, and a motor M forrotationally driving the holding means 1911. The respective members willbe described below.

The holding means 1911 has a substrate placing portion 1913 on its uppersurface for placing and holding the semiconductor substrate W. Thesubstrate placing portion 1913 is adapted to place and fix thesemiconductor substrate W. Specifically, the substrate placing portion1913 has a vacuum attracting mechanism (not shown) for attracting thesemiconductor substrate W to a backside thereof by vacuum suction. Abackside heater 1915, which is planar and heats the surface, to beplated, of the semiconductor substrate W from underside to keep it warm,is installed on the backside of the substrate placing portion 1913. Thebackside heater 1915 is composed of, for example, a rubber heater. Thisholding means 1911 is adapted to be rotated by the motor M and ismovable vertically by raising and lowering means (not shown).

The dam member 1931 is tubular, has a seal portion 1933 provided in alower portion thereof for sealing the outer peripheral edge of thesemiconductor substrate W, and is installed so as not to move verticallyfrom the illustrated position.

The shower head 1941 is of a structure having many nozzles provided atthe front end for scattering the supplied plating liquid in a showerform and supplying it substantially uniformly to the surface, to beplated, of the semiconductor substrate W. The cleaning liquid supplymeans 1951 has a structure for ejecting a cleaning liquid from a nozzle1953.

The plating liquid recovery nozzle 1965 is adapted to be movable upwardand downward and swingable, and the front end of the plating liquidrecovery nozzle 1965 is adapted to be lowered inwardly of the dam member1931 located on the upper surface peripheral edge portion of thesemiconductor substrate W and to suck in the plating liquid on thesemiconductor substrate W.

Next, the operation of the electroless-plating apparatus will bedescribed. First, the holding means 1911 is lowered from the illustratedstate to provide a gap of a predetermined dimension between the holdingmeans 1911 and the dam member 1931, and the semiconductor substrate W isplaced on and fixed to the substrate placing portion 1913. An 8 inchwafer, for example, is used as the semiconductor substrate W.

Then, the holding means 1911 is raised to bring its upper surface intocontact with the lower surface of the dam member 1931 as illustrated,and the outer periphery of the semiconductor substrate W is sealed withthe seal portion 1933 of the dam member 1931. At this time, the surfaceof the semiconductor substrate W is in an open state.

Then, the semiconductor substrate W itself is directly heated by thebackside heater 1915 to render the temperature of the semiconductorsubstrate W, for example, 70° C. (maintained until termination ofplating). Then, the plating liquid heated, for example, to 50° C. isejected from the shower head 1941 to pour the plating liquid oversubstantially the entire surface of the semiconductor substrate W. Sincethe surface of the semiconductor substrate W is surrounded by the damemember 1931, the poured plating liquid is all held on the surface of thesemiconductor substrate W. The amount of the supplied plating liquid maybe a small amount which will become a 1 mm thickness (about 30 ml) onthe surface of the semiconductor substrate W. The depth of the platingliquid held on the surface to be plated may be 10 mm or less, and may beeven 1 mm as in this embodiment. If a small amount of the suppliedplating liquid is sufficient, the heating apparatus for heating theplating liquid may be of a small size. In this example, the temperatureof the semiconductor substrate W is raised to 70° C., and thetemperature of the plating liquid is raised to 50° C. by heating. Thus,the surface, to be plated, of the semiconductor substrate W becomes, forexample, 60° C., and hence a temperature optimal for a plating reactionin this example can be achieved.

The semiconductor substrate W is instantaneously rotated by the motor Mto perform uniform liquid wetting of the surface to be plated, and thenplating of the surface to be plated is performed in such a state thatthe semiconductor substrate W is in a stationary state. Specifically,the semiconductor substrate W is rotated at 100 rpm or less for only 1second to uniformly wet the surface, to be plated, of the semiconductorsubstrate W with the plating liquid. Then, the semiconductor substrate Wis kept stationary, and electroless-plating is performed for 1 minute.The instantaneous rotating time is 10 seconds or less at the longest.

After completion of the plating treatment, the front end of the platingliquid recovery nozzle 1965 is lowered to an area near the inside of thedam member 1931 on the peripheral edge portion of the semiconductorsubstrate W to suck in the plating liquid. At this time, if thesemiconductor substrate W is rotated at a rotational speed of, forexample, 100 rpm or less, the plating liquid remaining on thesemiconductor substrate W can be gathered in the portion of the dammember 1931 on the peripheral edge portion of the semiconductorsubstrate W under centrifugal force, so that recovery of the platingliquid can be performed with a good efficiency and a high recovery rate.The holding means 1911 is lowered to separate the semiconductorsubstrate W from the dam member 1931. The semiconductor substrate W isstarted to be rotated, and the cleaning liquid (ultrapure water) isjetted at the plated surface of the semiconductor substrate W from thenozzle 1953 of the cleaning liquid supply means 1951 to cool the platedsurface, and simultaneously perform dilution and cleaning, therebystopping the electroless-plating reaction. At this time, the cleaningliquid jetted from the nozzle 1953 may be supplied to the dam member1931 to perform cleaning of the dam member 1931 at the same time. Theplating waste liquid at this time is recovered into the recovery vessel1961 and discarded.

Then, the semiconductor substrate W is rotated at a high speed by themotor M for spin-drying, and then the semiconductor substrate W isremoved from the holding means 1911.

FIG. 81 is a schematic constitution drawing of anotherelectroless-plating. The electroless-plating apparatus of FIG. 81 isdifferent from the electroless-plating apparatus of FIG. 80 in thatinstead of providing the backside heater 1915 in the holding means 1911,lamp heaters 1917 are disposed above the holding means 1911, and thelamp heaters 1917 and a shower head 1941-2 are integrated. For example,a plurality of ring-shaped lamp heaters 1917 having different radii areprovided concentrically, and many nozzles 1943-2 of the shower head1941-2 are open in a ring form from the gaps between the lamp heaters1917. The lamp heaters 1917 may be composed of a single spiral lampheater, or may be composed of other lamp heaters of various structuresand arrangements.

Even with this constitution, the plating liquid can be supplied fromeach nozzle 1943-2 to the surface, to be plated, of the semiconductorsubstrate W substantially uniformly in a shower form. Further, heatingand heat retention of the semiconductor substrate W can be performed bythe lamp heaters 1917 directly uniformly. The lamp heaters 1917 heat notonly the semiconductor substrate W and the plating liquid, but alsoambient air, thus exhibiting a heat retention effect on thesemiconductor substrate W.

Direct heating of the semiconductor substrate W by the lamp heaters 1917requires the lamp heaters 1917 with a relatively large electric powerconsumption. In place of such lamp heaters 1917, lamp heaters 1917 witha relatively small electric power consumption and the backside heater1915 shown in FIG. 79 may be used in combination to heat thesemiconductor substrate W mainly with the backside heater 1915 and toperform heat retention of the plating liquid and ambient air mainly bythe lamp heaters 1917. In the same manner as in the aforementionedembodiment, means for directly or indirectly cooling the semiconductorsubstrate W may be provided to perform temperature control.

The cap-plating described above is preferably performed byelectroless-plating process, but may be performed by electroplatingprocess.

Although certain preferred embodiments of the present invention havebeen shown and described in detail, it should be understood that variouschanges and modifications may be made therein without departing from thescope of the appended claims.

INDUSTRIAL APPLICABILITY

This invention is suitable to a substrate processing method, and moreparticularly, to those used to fill fine recesses formed on the surfaceof a semiconductor substrate with copper, thereby forming a copperinterconnection pattern.

1. A method of filling a metal in fine trenches in a surface of asubstrate, comprising: forming a metal film on a surface of a substratehaving fine trenches in the surface by electroplating, wherein anelectric field between an anode and the surface is adjustable by avirtual anode; polishing the surface of the metal film by pressing thesurface of the substrate to a polishing surface for removing a portionof the metal film, wherein the pressures pressing the substrate to thepolishing surface at a central portion and a peripheral portion of thesubstrate are adjustable, and cleaning the polished surface of thesubstrate with a liquid.
 2. The method according to claim 1, wherein themetal film is a copper film.
 3. The method according to claim 2, furthercomprising removing the copper film on an edge portion of the peripheralportion of the substrate prior to the polishing.
 4. The method accordingto claim 3, further comprising removing the copper film on the edgeportion of the peripheral portion of the substrate and on a backsidesurface of the substrate prior to the polishing.
 5. The method accordingto claim 4, wherein the edge portion is in the range of from 2 to 5 mmwidth from an edge of the substrate.
 6. The method according to claim 4,wherein the removing the copper film on the edge portion of theperipheral portion of the substrate prior to the polishing is performedby etching with a liquid.
 7. The method according to claim 2, furthercomprising depositing a protective layer on a surface of the polishedcopper film.
 8. The method according to claim 7, wherein the protectivelayer is a metal layer.
 9. The method according to claim 2, wherein theelectroplating comprises a first stage electroplating with a firstelectric current and a second stage electroplating with a secondelectric current.
 10. The method according to claim 9, wherein the firststage electroplating is performed in a first stage plating device andthe second stage electroplating is performed in a second stage platingdevice.
 11. The method according to claim 1, further comprisingmeasuring a thickness of the metal film prior to the polishing.
 12. Themethod according to claim 1, further comprising annealing the metal filmprior to the polishing.
 13. The method according to claim 1, wherein theelectric field is adjustable by the virtual anode so that the differenceof thicknesses of the metal film between the central portion and theperipheral portion of the substrate is reduced.
 14. The method accordingto claim 1, wherein the pressures pressing the substrate to thepolishing surface at the central portion and the peripheral portion ofthe substrate are adjustable to reduce a difference of thicknesses ofthe polished metal film between the central portion and the peripheralportion of the substrate.
 15. A method of filling a metal in finetrenches in a surface of a substrate, comprising: forming a copper filmon a surface of a substrate having fine trenches in the surface byelectroplating, removing the copper film on an edge portion of theperipheral portion of the substrate; cleaning a surface of the copperfilm on the substrate with a water; polishing the surface of the copperfilm by pressing the surface of the substrate to a polishing surface forremoving a portion of the copper film, wherein the pressures pressingthe substrate to the polishing surface at a central portion and aperipheral portion of the substrate are adjustable, and cleaning thepolished surface of the substrate with a liquid.
 16. The methodaccording to claim 15, further comprising annealing the copper filmprior to the polishing the surface of the copper film.